If you don't know much about cars then it's difficult to find a fair price. But these days we have the internet and can easily learn new skills. A few years ago I didn't know a thing about cars besides how to drive them and how to put gas in them. But I picked up a Chilton's manual for my Mustang and joined a Mustang forum. Fast forward to the present and I AM THE ONE giving car advice to others and teaching others how to fix things on their cars. I write hubs to help people fix their Mustangs (and some translate over to other cars/trucks). With today's easy access to the internet, it's not too difficult to find out if you're getting ripped off or even how to fix it yourself.
I personally do not take my cars to shops for 99% of work they need. For the most part, I can do it myself. For the very few things I would take my car to shops for, I have a very few select shops that I trust with my cars and I know they'll do the work for a fair price and do the work very well. I have a transmission shop back in Iowa who actually called me in to show me that the clutch I got (that was supposed to fit my car) didn't fit. The guy tried over 10 clutches from different Mustangs before he called me. In the end he got me an OEM clutch from FORD, boxed up the clutch I'd brought in, explained the problem with it in detail so I could relay it to the company, and got me the product number from the OEM clutch for the next time it needed to be replaced. And when I picked up the car, the owner hung around and talked cars with me for a bit. I wouldn't hesitate to take any of my vehicles back to that shop. It was just one of those little shops in a sort of bad neighborhood, but the owner ran it well and I admire him for that.