HeavenShallBurn said:
Fordham's is your friend.
http://www.fordham.edu/halsall/source/medievalprices.html
For the economy side of world building its actually extremely easy to set prices. Define the currency system and relative worth of various levels of currency. Like the entire copper-silver-gold/pence-shilling-pound array and fix the price of a staple item. I prefer to use the price of grain for this purpose. Then pick a historical period and use that as a baseline to determine the prices of other goods relative to the staple serving as baseline.
EDIT: Just saw 3catcircus's last post beat me too it. But at the same time the issue of which coins are being USED is effectively on another axis from what most of the posters here are discussing. They're talking about setting the relative pricing and value of items in context to the monetary system. Also working at a more fundamental level than the price control via economic system manipulation level they're not saying x shall be worth y as a king would, they're saying balance of commodities between x and y is z.
True, but the problem is, what most people are discussing does nothing to change the dynamics of the game. Saying "a silver piece is now worth what a gold piece was worth and a gold piece is now worth what 20 gold pieces was worth" and then turning around and saying "change all book prices to the next lower category" means that you are shifting the scale without changing the actual values involved.
By making the prices shift while at the same time making the coins more valuable as TwinBahamut suggested, you aren't making gold more valuable - you are making silver more valuable. The only easy-easy way to make it more valuable is to keep the book prices as-is while removing all of the platinum and the majority of the gold coinage from circulation. You are artificially creating the use of the silver piece as the basis of the economy this way, but it
isn't what the definition of a silver standard is. A silver standard only means that you are using a set quantity of silver to define the basic unit of currency. By doing what TwinBahamut suggests, you are forcing prices to fit the money instead of the other way around.
The original intent of the thread was to figure out if it made sense for people who are far apart and disconnected from one another to have gold as the primary medium of exchange, with JoeG's point being that copper made no sense as the standard
since prices are in gold, but making silver the standard would allow other types of metals to be used for coins while making gold and platinum really valuable.
The problem is one of, I think, semantics - due to the fact that the coins are referred to by their metal type, rather than some different name. "What do you mean that I can't use gp to buy this 50 gp armor?!?!" It is much easier to think of the coins as penny, dime, dollar. You can still charge $1 for something, but if all of the dollar coins/bills are removed from circulation, the buyer may be forced to pay in pennies or dimes (with nickels and quarters and half-dollars being fractional denominations.) A real example of what I am talking about is the US $2 bill (ignoring the fact that it is fiat money). There are $2 bills around, but most of them are sitting in banks rather than in retailers' tills. Wanna buy a $2 soda? Give the cashier two $1 bills. Same amount of money, different amount of physical pieces of money.