This what I did when my kids started driving. I bought them each well-used cars and paid cash. Both are insured for liability only. My agent told me that the value or type of car doesn't matter, that the premiums are all (nearly) the same. I told each that if they get in an accident and it's their fault, the car is broken until they make enough money to pay and fix it.
I also told them that if they get a moving violation, that I would mail their license to my insurance agent with instructions not to return it for 12 months.
My youngest is now 19 and the oldest is 21, and neither has has any moving violations. The youngest has has two minor accidents, neither was her fault. On one she got hit from behind and pushed into the car in front, and the cop (wrongly) claimed it was her fault, so I paid to replace and paint both bumpers. The second, someone backed into her while she was parked (and reported it), so that was repaired by the other kid's insurance. The oldest slid on the snow and knocked over a mail box, but the damage was so slight we didn't bother to fix the car (but we did fix the mail box).
2005 4.0 MT dual exhaust GT mufflers GT suspension and wheels