I wouldn't allow a surgeon that injects fillers into the face to inject them into my body. I have heard of fat transfer for the thighs, but not for someone who wants a thigh lift. Fillers will probably not help you to achieve the results of an actual thigh lift, not to mention they are a temporary fix.
A $50 price cut is ok, but not great. This kind of a "deal" usually means docs raise the price on your grand total to make you "feel" like you're saving.
This site might help you to get a better grasp on fillers and their differences: Botox vs. Fillers: How To Choose The Best One For You (Beauty pro division)
I have only had Restylane twice (lips) and Juvederm and Juvederm Plus are way better by far. But I'd never put any of them in my thighs, personally.