An alternate currency that one has to convert real money into in order to participate in a private market.
It is common for funny money conversion denominations to be larger than anything available to purchase, so the market gets to keep the extra (which typically cannot be converted back into real money).
The map pack is marked at $8, but it's onthe Xbox store so you have to buy $15 worth of Microsoft funny money.
When you go out to a club or a party and you expect the price to be 12 dollars but it cost 18 to get in and you have to ask a friend to borrow it. You have funny money.
