I learned the hard way, cost is second only to safety. There's a high probability for dents and scrapes, at the very least, so a first car needs to be cheap enough that damage won't hurt your wallet or your heart.
I would have a hard time buying my teenager a nicer car than what I drive. my first car was a 1970 Ford Pinto. I had to buy it with my own money. I loved that car, and I took better care of it because I bought it. My dad taught me basic car maintainence like how to check the fluids and tire pressure, he even taught me how to change a flat tire. I don't think parents should buy expensive cars for their kids.