If you want to get ripped off, then go to the dealership. They especially prey on people who don't know squat about automobiles. I use to go to them and act like I didn't know anything just to see what they'd tell me. It was amazing some of the responses I'd get as to what was wrong with my car, when I knew what they problem was. I took my Mercury in a couple years ago because the "Check Engine" light came on. The told me I needed a new catalytic converter (around $1200 total). I took it to my mechanic and he put it on his tester and found a short in a wire (under $100).
They have tried to take advantage of my Mom on numerous occassions. I guess thinking they are dealing with an elderly lady they could get away with it. They just didn't realize she has three sons who know automobiles and advice her.
I do the routine maintenance on my vehicles myself. But they have made cars so computerized, and made cars today so hard to work on, it's hard anymore to "do it yourself". It use to be no big deal to replace a starter, radiator, and numerous other basic equipment. Nowadays, once you pop the hod, you can't even find it.
I have a local mechanic that I have come to trust. You need to build that loyalty. He gets all my business and he knows it. So he treats me right and gives me good deals. I know when I go into the guy he's not gonna give me the runaround or try to sell me needless repairs.