I'd go through RockAuto.com rather than Amazon, amazon doesn't do a good job of giving you the right part for your vehicle. My husband (mechanic) just loves RockAuto, since he found them he won't shop anywhere else.
I use Rockauto, Amazon and Ebay for most of my auto parts shopping. You do have to be more careful usually on Amazon and Ebay that you're getting the right parts and that they're good quality. When I have several items to buy, I usually end up at Rockauto, since shipping starts out high, but doesn't go up much with more items. I love the 'choose for me to minimize cost' tool on Rockauto.
That said, I have a beef with Rockauto right now over a brake hardware kit. Apparently, some Toyota Siennas have only rear drums brakes, instead of the disc and parking brake drum combination that I have. A note to that effect would have saved me alot of headaches and the expense of having to run to the local parts store and shell out way too much for the right hardware in the middle of the job. All that to say, even at Rockauto, you have to know what you're looking for.