I'm surprised that there aren't more currency comparison PPTs out there. When explaining the rules of a 'Price is Right' game or the like, I usually insert a slide or two of this powerpoint into the existing one just for a quick review. Each game is different so cut and paste as you see fit.
This is a quick, clean presentation that I whipped up and thought I would share it. Like always, feel free to modify and share as you deem necessary. Hope it helps!
UPDATE: added printable American money.hwp with 1s, 5s, 10s, 20s, 50s, and 100s but I usually only print pages 1-4. Also, I added a small space in between the clomun of bills which, if you prefer, you can delete to make them stand side by side.
http://www.box.net/shared/bx10qu7fr0