You need to be able to check out the cab yourself. Thats like me saying Ill sell you my car right now, but it doesnt turn on. That could be a bunch of problems! You need to look at it and take your time until you figure out the problem, but dont make it obvious, pretend you're stupid. That way you can say itll cost you a bunch and all that stuff. Example:
I was at some warehouse place and there was a 512mb MP3 player. It was selling for a few hundred canadian. It had a small scratch by the volume control and for some reason it wouldnt turn on. I looked at it, found that the battery connection was crappy, but instead of yelling " OH THATS EASY ", I played dumb. I insisted it would cost a bundle to even be able to turn it on and that without any expansion cards for space (the guy didnt see it had 512 mb, he though it was empty) that it was rendered useless. I bought it, twisted the little spring a bit, and I now have a full mp3 player for TEN CANADIAN DOLLARS! It has FM radio and all that crap too...
Although this has nothing to do with your situation, just take my advice and act stupid. You don't know whats wrong and to pay someone to look at it will surely cost alot.