Seems like this came up in reference to C.A.R.S. or something else recently, but I happened to be searching for a different model and ran across these. Figured this was as good of place as any:

Some are, obviously, better than others.

TurboSquid is sort of like an where independent artists/modelers can put up their wares for sale in one centralized place. In the case of TurboSquid it's all 3D modeling, textures, etc.