I have a 2001 toyota camry, low mileage. The guts are in good shape, and it should last for years more. I've had most of the major repairs done and necessary stuff (timing belt, brakes, new tires, etc...), though there have been some minor annoyances that have added costs (window motor failed, door handle snapped off; both required disassembling the door which was costly). I've probably averaged about $1000/year on it for the past 4 years; some of that stuff, especially the timing belt and brakes, are 1-time repairs, but I'm not sure what else will come in the future.
The mileage on the car is mediocre; 28ish on highways, low 20s in town. However, I have minimal insurance on it which is nice. The other big purpose of the car is that I park it outside, and I don't drive it a lot; 5000 miles/year tops. So I figure an old junker is good for just sitting there and being exposed to the elements, especially in the upper midwestern state I live in where winters are long and hard.
Anyways, trying to decide if i should keep it or trade it in for a used car with better mileage. My gut instinct is to stick with what I have since I drive it so little and it would take a while to earn back what I save in mileage.