Buying an old car you need something that doesn't break, or something that is easy (cheap) to fix when it does.
Cars that fall into the first category include Toyotas, Hondas, Mazdas, pre-1990 Mercedes Benz. Cars that fall into the second category are Ford and GM, Hyundai.
Jeep lets you down on both counts, but if you have to have one, buy on condition not mileage. Check out the owner as much as the car.