Fantasy Currencies

I was putting together a Word of Trade for Godbound the other day (I just kitbashed it from existing Gifts) and it made me think about fantasy currencies.Fundamentally, currency is an abstraction that makes barter easier. If I have a bunch of chickens and want to trade some of them for a goat, currency makes it so we don't have to figure out and agree on a chicken:goat conversion factor every time. Instead, I know how many dollars a chicken is worth and a goat is worth, and that gives us a number of chickens per goat. It lets us engage in a simplified trade based on our shared understanding of the value of the currency we're using.Of course, that shared understanding is based on something, and there have historically been a lot of ways for it to grow. Traditionally, RPGs usually use the precious metals as currency method, something which is believed to have intrinsic value. (It doesn't actually have intrinsic value; it has intrinsic difficulty. But we'll get to intrinsic value in a…