Things can definitely be had cheaper than Crutchfield at Amazon, Sonic Electronix, onlinecarstereeo.com, etc, but like I mentioned above Crutchfield includes any adapters, wiring harnesses, and install kits needed, which shrinks the price gap and saves some time hunting them down yourself. At that point I usually don't mind paying a little extra to a company that provides excellent service.
Question that you (or someone else in this thread) may or may not know. My car has bluetooth from the factory. Worked fine originally and then there was some glitch that kept it from pairing with devices. There was a TSB on it but I'm out of warranty now. I think the dealer wants $100 now (ridiculous for a software fix I know).
So the question is, if I were to get a new head unit with bluetooth, would the software glitch in the car keep it from working, or does the new unit provide all the bluetooth connectivity required? If I'm going to spend $100 might as well spend a little more and get a better head unit, is my thinking.