Buying cheap to fix, good idea?

I have a friend who likes to restore RV's and thus buys scrap trailers from a local RV bone yard and then rebuilds them the way he wants them. Even built his own tow vehicle out of an old ambulance. He just bought another old ambulance to build a new tow vehicle. Depends upon your skill set and how cheap you can get the unit. Dealing with salvage title is can be different but he built an awesome 5er.