As a painless way to save money, a young couple arranged that every time they have sex the husband puts his pocket change into a China piggy bank on the bedside table. One night while being unusually athletic, he accidentally knocked the piggy bank onto the floor where it smashes.
To his surprise, among the masses of coins, there are handfuls of five and ten dollar bills. He asks his wife "What's up with all the notes?", to his wife which replies, "Well, not everyone is as cheap as you are."