Exact Change Please

I have always wondered why some grocery stores price their products with a denomination of 1 centavo, (e.g. 14.31 pesos) eventhough the smallest centavo denomination is the 5-centavo coin. Thus, if the an item is priced at 14.31 pesos, you are forced to pay 14.35. And since there is no denomination less than 5 centavos, you'll never get that 4-centavo change. So, you'll be paying extra 4 centavos for that item. This difference might seem negligible, but if hundreds or even thousands of customers pay these extra cents, the grocery store would have more and more profit. Haha!!! How wise of them.
I demand my exact change.