Dollar Bill Origami. Got money to fold? $5.95.
This helpful book guides you through simple origami steps to create 15 different shapes from a squid to a Jedi to an Oriental dragon and more. Spiral-bound hardcover; 80 pages including U.S. Currency trivia
We have dollar origami in Canada, but the coins are harder to fold. :-)
As a starving student, I discovered that you can be a completely cheap b*d if you fold your money into something cute. People will totally overlook an under-10% tip as long as part of it looks like a teddy-bear.