When I worked fast food, a customer paid with a few $2 bills. It wasn't strange to me. But when I tried to hand them as change to another customer, they looked at me like I was an idiot and demanded that I pay them in real money.

Before then, I was cashing my paycheck at a bank. I'd occasionally ask them for $50 of it in $2 bills. The bank had them approximately half the time, and it was fun to pay for things with them.