We gave our daughter a credit card when she got her driving license at 16. We wanted her to be able to use the card for gas and for emergencies. If it wasn't an emergency or wasn't for gas, she had to ask us ahead and had to bring home the receipt. This worked fine. Now she is in college and we are glad she can order online - same rules, asking us ahead and saving the receipt.  We always pay off all our credit card balances each month, so we view her use of the credit card as a convenience.