A'koss said:
Through the years we've probably tried every iteration for coin weights the various editions and Dragon articles could come up with. The lighter coins have that nice potability factor working for it, but I missed the days where the PCs would have to hire
caravans to haul their treasure out of a dungeon.

High level 1st ed. and Companion/Masters set adventures would hand out small mountains of coins and gemstones the size of men's chests. I still remember modules like Sabre River, the dragon's horde having well over
1,000,000 gp...
I remember those modules well, it was kind of disappointing to see how small treasures became in 3e. Thing is with how they arranged the magic item situation they had to cut back on gold to prevent its use for purchasing magic items that would damage the balance of the game.
This very same thing was brought up in the Gold vs Silver standard thread.
http://www.enworld.org/showthread.php?t=216975&page=1&pp=50
And this was my answer.
:) said:
High-end magic items had ridiculous prices in gp in 3e, I mean once you got past the first couple + equivalents you're talking about hundreds of pounds of gold. Yet with various conjuration, creation, or summoning spells raw materials of any kind become trivial past a certain level. Want platinum summon a djinn and have it provide, bind a lantern archon and produce potentially thousands of everburning torches, etc. Now if you follow this logical course simple specie currency is purely a artifact for the unwashed masses. Above a certain level it becomes worthless since characters of that level can effectively have as much as they desire via magic.
What this means is while there can be a trade in high-powered magical items they can't be bought for anything so crude as a raw material beyond a certain level. Beyond 15,000gp you can't buy it with gold or silver or even platinum. It takes souls, or gems useful as spell components, or weird planar currencies based on things like raw chaos, bottled pain, high level scrolls, etc.
Key thing is that you allow smaller magic items to be bought in the specie economy. Because beyond a certain point these things aren't an important power boost anymore so having lots of them isn't a great help. Whereas more powerful magic items are by their nature potentially more disruptive if available early or too easily. But you still want to be able to properly reward PC via "money". So instead you have that cut-off point, beyond it mere specie is worthless and it takes something cosmologically valuable like souls-chaos-xp-expensive spell components-favors of extraplanar beings-whatever. It serves the dual purpose of granting more DM control over the powerful items while separating them from the specie economy so that PCs can plow their wealth into things beyond the highest tier of mechanically optimum magic items.
I got the idea from the economics section of The Dungeonominicon over on the WoTC boards. It lets me go old school with the treasures and not have it unduly impact the game because you can't buy powerful game altering magic items with mere gold/silver/platinum.
Important sections of the Dungeonominicon for this are in the spoiler below and the full document is attached.
[sblock]The Economicon: Making Sense of the Gold Standard:
"100 pounds of gold for a house? How does anyone make rent without a wheelbarrow?"
Since time immemorial, D&D has used the "gold piece" as its primary currency. It is apparently a chunk of reasonably pure gold of vaguely standardized weight that people use fairly interchangeably in different cities populated by different species. In the bad old days, each gold coin was a tenth of a pound, which was hilarious and inane. In the current edition, each gold piece is a fiftieth of a pound. That's 3.43 gp to the Troy Ounce, which means that in the modern economy, each gp is about $171 worth of gold. Obviously, gold is significantly more common in D&D than it is on Earth, gold is also undervalued because its status as a currency standard drives it out of industrial uses and causes inflation. Further, populations in D&D are orders of magnitude smaller than they are in the real world, so the gold per person is higher even with the same amount of gold. So the gold piece is massively less valuable in D&D economies than it would be in Earth's economies.
Nonetheless, things are really expensive in D&D, and the high price in gold means that there's a distinct limitation of how much wealth can be transported by any means available. The economies of currency transaction are actually so unfavorable that currency as we understand the term does not exist. Things don't have prices or costs – all transactions are conducted in barter and a common medium of exchange is heavy lumps of precious metal.
Wish and the Economy
An Efreet can provide a wish for any magical item of 15,000 gp or less. A Balor can greater teleport at will, but can only carry 30 pounds of currency while doing so. Even in platinum pieces, that's 15,000 gp worth of metal. The long and the short of it is – at the upper end of the economy currency has no particular purchasing power and magic items of 15,000 gp value or less are viewed as wooden nickels at best. You can spend 15,000 gp and get magic items, but people in the know won't sell you a magic item worth 15,001 gp for money. That kind of item can only be bought for love. Or human souls. Or some other planar currency that is not replicable by chain binding a room full of Efreet to make in bulk.
Powerful characters actually can have bat caves that have sword racks literally covered in 15,000 gp magic items. It's not even a deal because they could just go home and slap some Efreet around and get some more. But even a single major magic item – that's heavy stuff that such characters will notice. Those things don't come free with hope alone, and every archmage knows that.
Coins are Big and Heavy
"How many boards could the Mongols hoard if the Mongol hordes got bored?"
From the standpoint of the adventurer, the primary difficulty of the D&D currency system is that the lack of a coherent banking and paper currency system means that there are profound limits to what you could possibly purchase even with platinum. But the currency system hurts on the other end as well. Untrained labor gets a silverpiece a week. That's 500 copper coins a year, which means that no matter how cheap things are they can only make one purchase a day most of the time. That's pretty stifling to the economy, in that however much gets produced, noone can buy it. Demand, from the economics standpoint, is strangled to the point where large production outputs don't even matter (remember that in economics Demand doesn't mean "what people want", it means "what people are willing and able to pay for", so if the average person only has 500 discreet pieces of currency per year, that puts an absolute cap on economic demand, even though the people are of course both needy and greedy enough to want anything you happen to produce).
What's worse, those coins are heavy. For our next demonstration, reach into your change drawer and fish out nine pennies. That's a decent lump in your pocket, neh? That's about one copper piece. Gold pieces are smaller (less than half the size, actually), but weigh the same. D&D currency, therefore, is more like a Monopoly playing piece than it is like a modern or ancient coin. There's no reason to even believe these things are round, people are seriously marching around gold hats and silver dogs as the basic medium of exchange.
Now, you may ask yourself why these coins are so titanic compared to real coins. The answer is because having piles of coins is awesome. Dragons are supposed to sleep on that stuff, and that requires big piles of coins. Consider my own mattress, which is a "twin-size" (pretty reasonable for a single medium-size creature) and nearly .2 cubic meters. If it was made out of gold, it would be about 3.9 tonnes. That's about eighty-six hundred pounds, and even with the ginormous coins in D&D, that's four hundred and thirty thousand gold pieces. In previous editions, that sort of thing was simply accepted and very powerful dragons really did have the millions of gold pieces – which was actually fine. Since third edition, they've been trying to make gold actually equal character power, and the result has been that dragon hoards are… really small. None of this "We need to get a wagon team to haul it all away", no. In 3rd edition, hoard sizes have become manageable, even ridiculously tiny. When a 6th level party defeats a powerful and wealthy monster, they can expect to find… nearly a liter of gold. That is, the treasure "hoard" of that evil dragon you defeated will actually fit into an Evian bottle.
There are two ways to handle this: Live with the fact that treasures are small and unexciting in modern D&D.
Live with the fact that characters who grab a realistic dragon's hoard become filthy stinking rich and this fundamentally changes the way they interact with society.
But once you accept that the realities of the wish based economy, you actually don't have to live with characters unbalancing the game once they find a real mattress filled with gold. That's not even a problem once characters are no longer excited by a +2 Enhancement bonus to a stat or a +3 enhancement bonus to Armor. Which means somewhere between 9th and 13th level it's perfectly fine for players to find actual money without unbalancing the game. Really, you can stop worrying about it.
Powerful Creatures Have a Powerful Economy:
The amount of gold it takes to get anywhere as a land lord is very large. The question that arises then, is why awesome architecture exists at all. It's a valid question, the listed costs to put things like pit traps and thrones made of bone into your dungeon are stupendously large and actual magical swag can be made available for much less than that. The answer is that: People don't actually pay all that gold to have their homes remodeled (see the peonomicon below).
Powerful artificers and adventurers don't even want your gold. If something has a value of 100,000 gold pieces, it can't be purchased with gold pieces at all – because that's an actual ton of gold that you'd have to plop over the counter and the merchant you're dealing with won't take your money even if you have it.
Here we're going to be focusing in on
Gems
Souls
Concentration
Hope
Raw Chaos
Gems: Truth or Dare:
Gems are, to the vast majority of participants in the economy, pretty much worthless. A 500 gp diamond is pretty much the same as a gold piece to someone who intends to purchase things with a value of 1 gp or less. And of course, there are a lot more individuals out there who will stab a peasant in the face for a diamond than a gold piece. So why does anyone care?
Well, two reasons: the first is the obvious one that gold is extremely limited in what it can possibly purchase. A +2 sword is worth your weight in gold. Not its weight in gold, your weight in gold. It seriously costs over 166 pounds of gold, and that's just not reasonable for most people to put into their pockets. So people interacting with even the shallow end of the magic trade need there to be some crazily expensive items that have no purpose save to look pretty and be exchangeable for other stuff. But unlike our world gems actually have real value as well: as the fuel for powerful magics.
On Earth, the only reason that a diamond is expensive is because there's an international organization called DeBeers that seriously has actual assassins that will shoot you in the face if you try to sell diamonds for less than the price they've determined that they're supposed to be sold for. D&D doesn't have that kind of armed monopoly to maintain gem prices, but it does have the fact that people continuously use up gems for spells like raise dead and item creation and the like. So the fact that you can use ruby dust to make continual flames that you can turn around and sell as Everburning Torches means that ruby dust will continue to have value as long as people value light.
The D&D rules actually only go into the spell component uses of a handful of gems, but rest assured that all the rest are similarly useful when we get into the ephemerals of item creation. A lot of those "components" that cost piles of thousands of gold pieces are actually just piles of gems. Onyx keeps its value based on the needs of necromancers, but amethyst is just as needed to bind illusion magic into a cloak. The exchange rate between gems and magic items is in no danger of going anywhere. Minor magic items and gems are traded avidly by shopkeepers, adventurers, and even powerful outsiders and wizards.
But even so, gems can be simply acquired by the very powerful. The realities of the wish based economy ensure that gems can simply be obtained in large numbers by anyone who really cares enough to dedicate a conjured earth elemental to collecting them. Magical items that cannot be created with the application of spells (that is, magic items valued at more than 15,000 gp) cannot be purchased on the open market with mundane currency, not even gems. That isn't to say that you can't cheat a goblin out of a staff of power with some shiny rocks, you totally can (heck, you could also stab the goblin in the face and take that staff of power), but doing so is not considered a "fair trade" and requires a bluff check on your part.
In addition, many D&D worlds posit the existence of magic gems, which can be used to make magic items, increase personal power, make a snazzy grill with the bottom row made of gold, and all kinds of stuff. In addition to getting hot women to ask you to smile, these magical gems are magical and are actually considered fair exchange in the near-epic economy. You can't wish for Eberron Dragonshards or Planescape Planar Pearls, so those things have real value to Efreet and other creatures participating in the Big Pond. Rules for using magic gems appear in the Tome of Tiamat.
Magical Currency
Souls: The souls of powerful creatures are trapped in gems and the trade in them is brisk on the outer planes, especially in the planar metropolis of Finality on Acheron. Once a soul is in a gem, the gem itself is of little or no value, but the soul goes for 100 gp times the square of the CR of the creature whose soul is trapped (see Tome of Fiends for more information on the use of souls).
Concentration: Ideas take form on the outer planes, and really pernicious or stellar ideas can be so powerful that they take a while to form. In the before-time, they can be found as an amber-like substance that is extremely valued on Mechanus, and by extension every single other outer plane as well. Concentration is actually made out of ideas, and while it looks like a solid object it is actually a liquid that flows so slowly that you could watch it for a year and only a Modron could tell you have far the flow had taken it. A pound of concentration goes for 50,000 gp to an interested party, and can be used in magical crafting by those with the patience to learn its secrets (see Book of Gears for more information on the use of Concentration).
Hope: Hope is funny stuff, it has lots of inertia, but those who carry it are not weighed down in the least. It has mass, but not weight. Even the smallest piece of Hope sheds light like a daylight spell (the effective spell level for this effect is 7, and Hope can overcome almost any darkness). Hope is measured in kilograms rather than pounds, and a kilo of Hope goes for 100,000 gp to those who want it, and it can be used in magical crafting (see Tome of Virtue for more information on the use of Hope).
Raw Chaos: The plane of Limbo is filled with possibility and change. Usually this manifests as a continuous creation and destruction that is awe inspiring and terrifying at the same time. Sometimes, for whatever reason this possibility doesn't become anything, and just stays as Raw Chaos. Raw Chaos can have any dimensions and any amount of mass, but from a practical standpoint you either have it or you don't. If you have Raw Chaos and someone else doesn't you can give it to them, and it is generally considered good form for them to give you magical items or planar currency worth 200,000 gp in exchange. Raw Chaos can be transformed into magical items by those with the correct skills (See Tome of Tiamat for more information on the use of Raw Chaos).[/sblock]