You got ripped off at close to $800. And did that include the parts kit or did you buy that on your own? A Continental Timing Belt kit is $86 on RockAuto. Even if that was upmarked to $200, you still got ripped off.
I would always ask a shop to break down the price between parts and labor when making an appointment. By the book, a timing belt on a 2004 Aveo is 1.6 hours.