Let your experience with that timing belt be a warning: they do not last for the life of the car, and must be replaced regularly (expensive, but less than a blown engine). If you buy a car with a timing belt, check the maintenance schedule and plan on replacing it no later than recommended. If it's overdue, find out how much that will cost--or walk away from the deal.
At the $5000 price level, the car will be old enough that condition and prior treatment are vital. Even the best brands will have problems if the car has been abused or poorly maintained. Get an opinion from an honest independent mechanic, one who works on many makes and knows what problems are common on different models, one who isn't afraid to tell you "If you buy that thing I'll be seeing you often." Also ask about how easy it is to find parts for the model you're considering; discontinued or unusual parts could keep it in the shop until a special order arrives.
Insist on a fresh emissions test, and check the numbers on the report to be sure it didn't barely squeak by. If it barely passes this year, there's a good chance it will fail next time. In most states, failing the emissions test means you can't renew the license plates until it's fixed.
I generally look for less than 10 years old and less than 100,000 miles. But I have had a car with multiple problems in less than half that, while another lasted far longer (same make but different models).
