Okay, so I read somewhere that the reason prices in D&D are so absurd (10 gold coins the size of your thumb for minor stuff a peasant should be able to afford) is because they're based off of byzantine prices in an era where the "gold" coins were heavily watered down. How much would you have to water down gold for a random agricultural worker to be able to get their hands on a "gold" coin? (Also, is the story in question true?)
I'd love to hear about Byzantine coinage too, but the original story is much simpler.
Dungeon Master's Guide (1st ed) p90:
"The prices and costs of the game are based on inflationary economy, one where a sudden influx of silver and gold has driven everything well beyond its normal value"