We have a mechanic now that constantly surprises us by billing us something like 2-5x times less than we expected. Turns out, he's good, and he bills us for actual time spent and parts cost. Like last time, I expected to pay ~$270, ended up paying $65 - $32.5 for parts, $32.5 for work time.

This guy only takes work from existing customers and people referred by them, because it's widely known in the local community that he's good, and has way more people wanting his services that he can handle. He could rise his prices, but it turns out, he's a decent human being.