TWWP Puzzler #1: Four one-dollar bills.

I’m a big fan of the NPR series “Car Talk,” which from time to time offers what they call a puzzler. Here’s a puzzler for you TWWP readers:

I went to a store a few days ago. I knew the bill would be under four dollars. When I took out my wallet I noticed I had four one-dollar bills. If you had been standing nearby where you could see my hands you would have seen me do something with those four one-dollar bills. What did I do? What does it tell you about me?