EDIT: PLEASE READ ENTIRE POST. I spent around an hour doing the math here... Least you can do before arguing it is look at all links and analysis .
I generally compare standards of living, and I have a hard time drawing an equivalency between the modern lifestyle of a citizen in the US or Western Europe and a D&D commoner. I generally imagine D&D fantasy worlds to be more like feudal Eruope where there simply was no middle class to compare with modern standards. Even skilled artisans were serfs, and couldn't expect much in the wealth department.
WFRP actually has a rather extensive explanation of what the common folk live like, and breaks the economy into three different teirs where peasants deal in brass, artisans, merchants and adventurers deal in silver and only the nobility deals with gold. Commoners will in all likelihood never see a gold piece in their lives.
In a D&D setting, giving a 10cp/day worker a gold piece worth 100 copper it's the equivalent of giving him ten days wage at once. You can adjust based on your perspective. Expensive magic items are a byproduct of an exponential weath by level growth, which is a big reason why I just say there's no market for them. You can say a +1 Longsword is worth the equivalent of $150,000, but if there's nobody to buy it then it's worth whatever it's sold for.
Alright... Looking over what you have here, let's try to figure out the basics of what we need to know to figure out, in D&D terms, a peasant family.
Personally
I go with a peasant family having 4 children, 2 adults as my rural 'mean' for living in a small cottage (20*20). This is the absolute serf 'max', assuming individuals are going to go occasionally hungry, produce most of their own food, and that the household is meeting 'subsistence' wages if the children are 'working' half wages by gathering fruits and berries, tending the fields along with their family from a young age, and scraping by. This family unit can produce
172 GP worth of materials pre-taxes. If we factor in tithes and taxes of around 25% of gross processed grain on that amount farming will yield 81.77 GP on an unskilled farmer's wages for a year's harvest, but you get to eat, sleep, and otherwise be alright with it.
So figuring the 2 GP of Self-sufficiency for 4 Adult's Worth of individuals you can figure 129.77 GP as the overall wages for a family of 6 working a wheat farm in a standard location without any Plant Growth or other addenda.
That's about 324sp worth of wages per adult unit, which means your kids are worth about 14.1 GP/year.
Federal Poverty Level guidelines.
Poverty Level for Repayment of Student Loans.
We can all consider these individuals to be poor, correct? The family of 6 is considered to be at the full mark of the poverty line at around 30k. If we take that as our number our copper piece is worth $2.31, with a gold piece being worth $231. That means that a gold piece (if translating to our own current gold prices and 50 GP/lb) is below 12k (50%) gold as a .999 gold coin (most minted coin purity) of 1/50 lb. would go for $478 on the open market today.
If these coins were made of pure gold we're looking at $62153 for the amount of gold, making the copper piece worth $4.78.
None of these numbers feel close to right for me for someone who is at this level of poverty. Personally I would put such subsistence farming at about half of our current poverty line... 6 individuals 15485 or 14995 (average to 15240).
At $15240 - 129.77GP means that a GP = $117.43.
A copper piece is worth $1.17. I am not figuring in the taxes as part of the approximation because, in our world, those taxes are going right back to you. Not so much for our peasants here.
That means that, for our examples...
A Longsword runs $1761. Not too bad, as a sword will run 3 days worth of work, and 24 hours of labor plus materials and costs? Going to be expensive.
A guard dog runs $2348.60. Low, most can run for between 5k for a low-training dogs, to 80k for an elite guard dog (which I would put as your larger 'riding dogs' anyways
).
A heavy horse is $35486. Now that sounds ridiculous! Of course you can purchase a slaughterhouse special for 200 bucks... But horses of any note can run you up quite high quite quick. Dressage mounts, who have been trained in haute ecole (a martial horse style) can go upwards of $100,000. For the purposes of our reading a peasant may invest in a Colt and maintain that animal (look at my rules for maintenance of horses and other stock for easy bookkeeping in the thread referenced previously).
A Poor Meal at a tavern is $11.70. About right if you aren't getting appetizers and drinking water in the US
.
Fine Wine runs at $1170. Pretty high, but then again 23.40 is also a little high for large amounts of table wine but of course this was during a period when viticulture was not going to spread rare vintages lightly.
D&D Loaf of bread is $2.34. Whole grain loaf of bread in the US? $2.29.
Riding Sadle runs $1170. On the low end of handmade saddlery from personal experience and seeing actual saddlers hocking their wares at horse shows.
Stabling: $58.50/day. Quite high for today's pricing... However you also aren't paying stablehands to remain 24/7 in the stables to prevent horse thieving. Up in the air.
Cab fare (20 miles): 70.20. Not bad figuring current NYC rates for a good rate of ~ 20 miles (JFK to Central Park) will run you around 45-68$. The actual rate would probably be around 65 most times of day so not bad.
All of these numbers seem to point towards some things being worth a lot more, some a lot less, and possible reasons for them. I picked these items at random, and haven't tested all of the available items. Any prices are based on personal experiences along with basic google searching... Didn't include links because I checked about 40 of them for this section and didn't feel like writing up a whole Cited page
.
Again... 1.10-1.20 is a good estimate, 1.17 is my personal estimate per figuring in 'current costs'.
Slainte,
-Loonook.
EDIT: So I also did the math for
overall food costs on average in the US. I placed 6 individuals with a family of 4 (9-11 yo children here) and two young men 12-13. $825.40/month for 'thrifty', 7.05 GP/month, 84.6 GP/year, around 2/3 of overall income for a year, which is actually cheaper than a family living on Subsistence according to the DMG by around 12 GP/year. So I figure the numbers show a little bit of a sway, but hit right around the mark.