I'm pretty sure this gets asked a lot. In my world there's a lot of different countries and all that. The countries all share the same currency, except for one, and that's because decades prior the government was overrun by barbarians so the cities basically govern themselves. I've looked into trying to research ancient Greece before the Persian invasion when the cities were states of their own, but from what I can tell they're too advanced for my liking. The city I have in mind isn't advanced nor poor; they just can't make trade with other cities because those barbarians still terrorize the country. They're well off enough that they can at least be satisfied with their lives and many are not starving. I'm wondering what currency would be used in such a situation, if it's currency at all rather than just internal trade? To mix it up even more, although trade is difficult, it's not near impossible, but since it is difficult, resources and items that are imported from other cities or countries are highly expensive and can only be afforded by the very rich of that city. I kind of have an idea of how I want to go with this, I just wanted some feedback on what I could possible do with this.