Hi maybe for the game you can download Used cars off the game site that members uploaded. Lets say you go to the site and type in Gavril D15 and you can get cars in modified stock needing some work dents/rust bad and parts cars like bad damage bad rust (if you add rust) engine failures burnt cars (if you add fire ).
And maybe used parts.
And upload images
and cars don't sell out just a free save file but the gamer will need the car he want to buy or it will crash.