I tend to check completed listings for the same item, then I think to myself would I get it for less than 25% lower than what it would fetch normally at a certain price range. I then factor in the possible cost of replacing such as the CRT or a major component and the value of the item as spare parts and if I am happy I purchase.
I expect honesty from any seller who has a professional knowledge of electronic items, more so If I find out they are a member of a forum such as this one, any less shows lack of morals, I feel there is no excuse to lie or deceive a buyer if you have this ability. Just be honest and say it is a dead donkey if it is. If I find the seller has limited or no knowledge of electronics then Caveat Emptor applies in my mind, in this case I would be looking at it and thinking " would I get more than the dollar I spent in spares on ebay or craigslist ". I know there are genuine bargains on Ebay, but be honest, if you truly think your going to get a piece of kit like this, even if outdated, for a dollar or two then you are kidding yourself,the seller isnt stupid and would know its worth if working, I would expect problems with it.