I have trouble finding a $20 bill in my wallet.
I found the $50 and one $100 bill in two different large shopping center parking lots. I had no idea from which store the losing party may have come from and they may have blown around in the breeze.
The second $100 was weird. I was getting in my car at a convenience store and a piece of paper blew across a field (no building on the other side, just trees) and right up to my foot. It was the bill. Absolutely bizarre.