Fantasy Money is a PDF product from E.N. Publishing, and it sounds pretty nifty. The idea is that instead of tracking your gold in fantasy games, the GM just prints out a pile of fantasy bills and you spend them at the table — just like in a game of Monopoly.
So when you loot the kobold caves and find 50 gp, 25 sp, the GM gives you bills in that amount. And when you want to buy a new sword, you just hand the GM enough money to pay for it.
The link above includes pictures of the cash, and offers up a good idea: print the bills in black and white on colored cardstock (or paper) to get the feel of colored money without actually printing in color.