I remember this was this flash game called Caravaneer 2 that had a really well fleshed-out economy system. In it, the prices of a commodity are determined by supply and consumption, which itself is made of many factors. For instance, smaller towns and tribes won't pay much for things like gold, oil, or soap because they have no demand for them and certain items, such as clothing, can take longer than other commodities, like beef, to be consumed. It's honestly quite impressive for a game that was free and is now like $6 on Steam. It also had communal economies in some areas if I remember correctly, most notably in the starting bunker and the surrounding tribes.