As an adult, your child will have to pay bills on time and manage their budget to ensure that they don't run out of money to pay their bills. If your teenager wants a car, use this opportunity to put the car in both their name and your name. This will help them build credit and take responsibility. When the monthly car payment bill arrives, hand it over to your kid and have them take care of the payment. This will teach them how to pay bills on time. Note: If they don't have the money or if you have volunteered to pay for part of their car payment, don't pay it for them, instead, give them the money as part of an allowance and have them manage it.