Whats' a AMC Rebel Machine worth???

There is a Guy local who has a green one.Myself I like the red,white,blue cars the best.I tried to buy a red,white,blue car here off a local classic car dealer.He found it in a barn and it was a one owner car.He didn't even have it unloaded from his tralier yet I offered him 10K.He wanted to clean it up and get more for it.I later learned he paid 5K for it.He could have made 5K off me by doing nothing more than towing it 25 miles back to his dealership.And if he would have said I will take 12K or 13K I would have bought it anyway.
Jim