Rabbit's advice is accurate (as usual).

In addition, I'd suggest that you not buy an Aveo that is before the year '09. (I have an '09, thankfully.) There were some major changes made in that model year, notably that the timing belt is now meant to last 100k miles.

The suspension is of a really cheap, crude design. I'd expect problems with that once the car has high mileage on it. There is a recall for the coil pack and plugs, but Chevy will do that for free if it hasn't been done already. The automatic transmissions get poor city mpg (20-24 mpg), but very good highway (40 mpg) at speeds above 45 mph. Routine maintenance is easy compared to most cars.

Every car has it's quirks. The later model Aveos are pretty good, considering that it's a cheap econobox car.