What is take a penny leave a penny?

"Take a penny, leave a penny" is a common practice at many convenience stores or small shops in the United States. The concept is simple - if a customer is short a few cents when making a purchase, they can take a penny from the designated container to make up the difference. Conversely, if a customer has extra change, they can leave their spare coins in the container for others to use.

This tradition is based on the idea of communal generosity and helping out fellow customers in need. It is a way to prevent small transactions from being held up by a lack of exact change and fosters a sense of goodwill among customers. While the amounts involved are usually small, the practice is a simple way for people to help each other out in small, everyday situations.