Buying a car in Chile for 6 month usage (Santiago de Chile)

My son is doing a 6 month internship at the HuiloHuilo Nature park and wants to buy a car for the 6 month he is there...He needs some kind of transportation to get around.

How do you get a cheap car and resell it when you leave... can a German/American 19 year old on temporary stay purchase a car and own it temporarily ?

Maybe someone can give me some advise :-)

Greetings from Nuremberg Germany
Matthias