I've seen a complete, well skinned low poly Camaro for $1.00 on another website, yet you want to charge $15 for a horribly skinned box that any newb on this board could make in 10 minutes?
Sorry if I sound mean but I question the sanity of somebody that would pay that much for these models. I would charge at most $0.10 for one of these models, but I think that would be an unfair price too. Not to mention there are trademarked logos on these models so whoever does use them in their game would have to pay additional fees to use.