Making the world better, one answer at a time. In the state of GA, the legal age to buy a car is 17. However, with parental assistance, a child of any age can buy a vehicle, as long as the car is in the parent's name. In the state of GA, the legal age to buy a car is 17.  However, with parental assistance, a child of any age can buy a vehicle, as long as the car is in the parent's name.