Tubby

Slang term for the US 20-Dollar-bill, as of the 2016 edition containing a picture of Harriet Tubman.

Cashier:How can I help you, Miss?
Jackie: Could you break a tubby for me?
Cashier:Sure. How do you want it?
Jackie: Could I have two 5's and the rest in ones?
Cashier:Well, I have some 5's, but I don't have enough 1's. Are quarters fine with you?
Jackie: Oh, that's even better! In that case, I won't have to worry about the small change for the laundry.
Cashier:Here you go!
Jackie: Thanks a million!