1: Looks like Monopoly Money.
2-4: Look like checks, not bills.
5: One of my favorites, especially with Ben Franklin giving you a criticizing stare for what you're about to use that $100 for.
6: WTF?
7: Probably my favorite. Organized and much different from our current bill.
8: Boring.
9: Horrific photoshop job that's too much like our current bill. Probably the worst design.
10: Uh....What's it supposed to represent, exactly?
11: Not bad, but needs some tweaking on the shading.
12: Way too much going on. Needs to be cleaned up, especially the backgrounds.
13: BO! RING!
14: Another of my favorites, though it could use some more color.
15: Very well done, but needs some better organization.