The trouble with selling a 17" LCD which is not working, is that there are so many available cheaply which do work. The fact that you have sold a used laptop screen in the past is an entirely different matter...without a screen, a laptop (which may be worth hundreds of dollars or more) is practically useless, so a person would be willing to pay some money to get it working again. A regular LCD screen, on the other hand, is pretty much a throw away item these days.
As for Patio, I beleive he may have been having a joke with you.
Good luck.