I am the Lawspeaker of Aurelia, and I decide to craft my awesome currency named Dong, to do this I first have to make the Dong Coin press, the game checks to see if Dong has been taken by anyone, if not I get to make it. I can then manufacture Silver Dongs, Copper Dongs, and Gold Dongs to my hearts content. I also have the sole ability to make more Dong Coin presses and hand them out to my trusted bankers.
After that all I have to do is buy up people's junk for my new Dongs and use said junk to do public works around Aurelia. Then I have started to circulate money. Example.
I, Cake_Tan have recently sold X for the amount of 5 q80 Silver Dongs. Some weirdo from a nearby village comes up wanting to buy X and has 5 q10 Durps. He is a fool for his Durps are made of a very impure silver, my awesome X are worth 40 q10 Durps, so he better pay up properly. (I don't actually know quality:value ratio so meh)
Now our rival village of BeakLand has started to smith a q80 Silver Anime, and they claim this Anime is worth the same as my Dongs! So the only choice is to go to BeakLand, kill them all, and get rid of any Anime Coin presses. How ever that is messy business.
Now to fix this coin rivalry it should be that a person needs a certain height of the Perception skill to be able to see the value of a coin.
Currencies are rewarded for uniformity. If those with high perception begin noticing that some animes are of a lower quality, they'll raise their prices in animes. The anime falls in value against the dong. The common folk with low perception have no way of knowing how much the anime they have are really worth, so they begin using the more reliable dong.
So if the minter tries cheating by devaluing his currency, he runs the risk of it becoming worthless. Example.







So for every common folk, the word of The Empire of Aurelia and there awesome q80 Dongs is just accepted fact, and The Dong is a highly valued currency, while The Anime is just shotty work thats not as worth as much as The Dong. This would create a need for money handlers and exchange people probably, give people something fun to do.