After the U.S Civil War, about 33% – 50% of all U.S. paper currency in circulation was counterfeit.

It would be mighty interesting to have players run into some money issues. Some examples of the characters running into fake money could cause the following interesting problems:

• Players accidentally pay in fake currency. If they are operating all over the place they could rack up a bad reputation over a long distance. It would be a pretty tough problem for the players to solve in order to make amends, if they even take that route.
• The players get paid in fake currency! Knowing most players this could result in some pretty bad blood between the players and some important people.
• The players could be sent out to hunt down the organization counterfeiting money. Who knows maybe a rival kingdom is trying to destabilize another kingdom by flooding their markets with fake coin.
• Or the fake currency being spread could be cursed in some way to fit into some evil nasties.

Any other thoughts on adding in counterfeit monies to your game?