Lets say you were given an A/c machine made by robinair. Machine needs a high side pressure guage and says it has 19lbs of freon inside it with no external tank attached. 1. do you need any sort of license to sell that sort of equipment? 2. How much would you pay for the machine if it needed work? (High side pressure guage, not sure if vaccumm pump works, storage tank needs to be drained) Weird situation huh? Lol.