Bernie Marcus used to warn salesclerks that he would bite off the finger of the next one he caught pointing a customer toward where to find something. (The clerk is supposed to walk you there and chat you up about your project along the way.) Marcus would have a mouthful of digits if he had followed this reporter over the last few weeks.
As a way to teach the mechanics of credit, open up a credit card offer and walkyour child through what it means to delay paying, carry a balance and pay interest.