Didn't "buy" them shit. Let them buy it and pay insurance (on our policy - check with your provider) so they can learn what it is to take care of a vehicle.
So, whatever they can afford within reason, especially if you're the co-insurer because as we know certain types of cars cost more to insure, let alone teenagers.
That means, something reliable like a Honda or Toyota. A sedan because that's cheaper to insure and they can fit their lowlife friends in.
Fortunately, I've been working on cars nearly my entire life so I was able to check out what they were considering and offer an opinion but at the end of the day, I let them buy what they wanted (mostly) and let them deal with it when the shit broke down and required lots of money to repair (an Audi for one).
Daughters made sure they at least got something reliable so they wouldn't have to depend on those grimy boys they dated.