The prices for Toyota parts are unofficially "fixed" throughout the country, because Toyota issues suggested retail prices (MSRP) for their parts, and the great majority of Toyota dealers stick to those prices. So if you call 10 different dealers in 10 different states for a price quote on the same part, odds are better than 8 out of 10 that they will be the same. I have a parts reference that lists the MSRP of all the parts for my Rav4, and the great majority of the time when I call a dealer, their price is exactly the same as what is listed on the reference. The reason prices for parts are so high is not that they cost so much, it's because there is a large dealer markup.
However there are some Toyota dealers out there that sell for under the MSRP, or offer discounts, but usually the discounts are offset by the cost of shipping.
Not to say you can't find discounts on Toyota parts, but they're hard to find from regular Toyota dealers. However, places like Brandsport sell a lot of OEM parts at less than dealer prices, and although most of the parts they stock are accessories, you can request a quote on any part and they can special order it.
I've never had to buy an OEM Toyota part that cost more than $100, so I usually just call up the local dealer and order it through them. Sometimes I get a 20-30% discount on parts like I did last month when I picked up the brake hardware.
Other than Brandsport , there is another parts dealer I have used with success, www.toyotparts4u.com, although most of their prices aren't any less than a regular Toyota dealer.