ニックネームハペニは
Penny is a nickname for the 1 cent coin in the U.S. It's more common to hear "penny" than "one cent" in daily conversation.
A cashier might say, "Do you have one/a penny?", and if the customer doesn't understand this, the cashier might repeat, "Do you have 1 cent?"
These are other nicknames for other coins
5 cents nickle
10 cents dime
25 cents quarter