First red flag - its free. Why is it free, or to rephrase it - why aren't the owners selling it to get the money? These types of homes in good condition sell for what, $10K, $20K? Remember the old adage: if it seems too good to be true, it probably is.

My advice would be to have a professional inspector check it out for you. It would be money well spent that could either give you some peace of mind or prevent you from getting stuck with a pig in a poke.