I ordered one Thursday from Beach Audio for 8 bucks shipped:
http://www.beachaudio.com/Metra/70-1761-p-46383.html
Even if heads from crutchfield come with a harness (I didn't think they did), you're paying a lot more than 8 bucks more than other internet dealers. They might be worth getting
speakers from for free wires and adapter mounts, but normally you'd choose them because they ship fast and have good customer service, not the installation extras. On that note, I wouldn't order from onlinecarstereo.com. I ordered speakers from them (75 less than crutchfield) on Wednesday, and they haven't shipped yet.
EDIT: Note if you have the premium sound package with your camry (component speakers with the door sail tweeters and an amp behind the glove box), there are 2 harnesses you can get. The one I linked bypasses the amp, and is not plugged in where the stock stereo plugs in. The harness the stock unit plugs into (15 pin) goes through the amp, then the wires come back and split to a pair of harnesses that the harness I linked will plug into. If you DO have the amp and DON'T want to bypass it, you'd need the 15 pin harness (probably the premium sound system one with RCA plugs for line-level output, which you'd have to patch onto the +/- wires going into the amp).
If you don't have the premium sound system, the model of harness I linked is the only one that works, and plugs in the same place the stock head unit plugs in.