This along with the T-Shirt are probably the easiest to make and something that anyone could start out with. Once you have it down you can rip these out in 30 to 60 seconds.

Difficulty : Beginner
Number of Bills : 1
Denomination Recommended : 1$ or 2$.
5$, 10$ and 20$ (new ones) have the portrait off-center. Not pretty.
Credits : Originally found from this Money Origami site.

Diagram [PDF]

Front
Bow Tie 01-01
Front Angle
Bow Tie 01-02