From the way all of you talk you must have treated your parents like $hit! He listens to his parents, is that so bad? If he just does what he wants I bet he'll be out on his own and probably wouldn't even have enough money to drive ANY car.
Whatever you do DO NOT buy a 6 cyclinder version of a mustang or camaro. I bought after high school because of high insurance on the 8's and I regret it to this day. (I still drive it). I should have just saved up and bought something older and more badass. Get an old 60's or 70's car when you have enough money. Dirt cheap classic car insurance and it's a lot cooler than a 99 camaro. Get something on the small side like a mustang with a 289 so you don't completely go to $hit on gas mileage. Just have to make sure it's not a basketcase.