Loose change, small change is a real problem, and what tends to happen is you buy a bunch of stuff, you're due, say, 10 cents, 20 cents in change. The shopkeepers tend to give you things like an onion or an aspirin, or a piece of gum, because they don't have small change.
El pequeño cambio es un verdadero problema; si uno compra un puñado de cosas, y le deben, digamos, 10 céntimos, 20 céntimos, los comerciantes tienden a darle cosas como una cebolla o una aspirina, o un chicle, porque no tienen cambio.