DD had a new Punto 1.2 for 4 years which was great and cost virtually nothing to run and has just traded it for a Peugeot Convertible.
DS wanted something a bit more trendy so had a 2 year old Punto Sporting, which was much more robust than the standard Punto, but still only a 1.2, but appeals to boys.
He wrote that one off on a wet windy lane ( outside our house) and then had another Sporting, which he wrote off on the M6- he had a blow out in the fast lane, so not his fault really.
He survived both withput a scratch. he now has a VW golf
Elephant were the cheapest insurers for DS and the premium reduced by putting myself and DD as named drivers on the policy.
Tesco was cheapest for DD. but increased the premium for named drivers, so it was in her sole name.
Do not be tempted to insure it in your name with your DS as a named driver to reduce the insurance cost, it is called 'fronting' and insurance companies are getting very switched onto it, and will not pay up in the event of an accident if they determine that your son is the main driver - particularly if you and DH have your own cars which DS does not drive.
You will have to bite the bullet on the insurance for the first year, get him to do pass plus, it reduced their premiums by a lot.
Make sure they can check the oil, tyre pressures and change a wheel and a bulb if need be.
I also bought a bag of stuff from the AA, - jump leads, warning triangle, torch, tow rope, Hi Viz vest etc, a blanket, bottle of water and some biscuits/chocolate that is kept neatly in the boot, if they are prepared it won't happen, if it does they are well prepared an won't panic.
Good luck, it scary having driving teenagers!