Taking my first car for inspection tomorrow, any tips to not get screwed over?

I know not all mechanics are bad, but I don't know a good one from a bad one. I haven't heard anything bad about these guys.Car is a 2007 Chevrolet Impala LS, by the way. New battery, oil change, new tires, and so on. Lots of cosmetic and interior flaws but under the hood is (afaik) perfect. My only true complaint is low freon, as a North Carolinian. via /r/cars http://ift.tt/2sYV59N