I ordered my Curt hitch from carparts, $87.49 with free shipping (and no CA sales tax). I am about to take the plunge on the Thule T1, 1.25" bike rack. Amazon has them for $299 with free shipping.
I've had my 09 Prius for about a month now and researched the hitch rack in detail. I've always used roof racks but wasn't about to ruin my MPG with a roof rack. I opted for the BVG rack which holds 2 bikes. It's the only one that you can actually lock the bikes on the rack not using a flimsy cable. The clamp that holds the bikes down is what locks. I've seen Pruis' with 4 bike racks but everything I read said it's not worth the risk to the car. All that's holding on the hitch are 2 somewhat small bolts. Good luck with whichever you choose. Thule is a good brand and if you're not too worried about locking the bikes on the rack, go for it.
