I just had my right rear bearing replaced, and I paid a whopping $250 for it (I didn't replace it by myself). It was worth every penny because of how quiet it is (and now I can actually listen to music w/o turning up the volume to the max)!

I would rather pay for somebody to do work on my car as opposed to me doing it because I get the peace of mind of a one year warranty on the part and labor (and, besides, I can't tell my ass from my hands when it comes to working on cars). Example: I had the bearing replaced on Monday, and I went back to the mechanic on Friday to bleed the brakes (brakes weren't spongy before bearing replacement). It took him about 20 minutes to do it, and he didn't charge me. The brakes now feel better than ever!!