I'd be careful with SupraSport..... a lot of crap hit the fan with them after some ownership changes and I have no idea if they're reliable now or not. They used to have a great rep a good while back, then it went to hell and now I have no idea.
I've found the eBay vendor
Mizumoauto to be a consistent and reliable source of OEM quality parts at very reasonable prices.
Horsepowerfreaks.com is an old favorite for most performance components.
Siliconeintakes.com is a great source for intake and vacuum components (more for turbo applications but still a good, cheap source for high quality vacuum tubing).
Champion Toyota (out of Texas) is a Toyota dealer and a good source for Toyota parts at good prices. They've come in lower than the shop discount I get from one of the local dealers in my area a couple times.
www.toyotaworld.com
Some parts I still buy through Amazon. I've found that some things such as AEM filters and cleaning solution is usually priced the best there (from reliable sellers).
NAPA for NAPA Gold oil filters (Made by Wix).
WalMart for for the best price on Pennzoil Ultra by the gallon (although I'm now running the Euro 5W-40 blend which as far as I've been able to find locally is only carried by the local Mercedez and Ferrari dealerships.... can you say pricey?
I'll order
online in the future.).
Sparkplugs.com for rotors, caps, plugs and wires.
That's about all for my regular shopping stops.