Myosmith

I know the prices for used bikes vary from market to market, but I bought both of our Treks for less than $100. The 820 Mountain trail is pristine with Altus components and needed no work, the 830 Antelope is has lower end Shimano components and needed a new bottom bracket ($45 for Shimano sealed BB installed at LBS) and was well used but otherwise in good riding condition.

Even at those asking prices, you would be money ahead with any of those three bikes compared to putting big $$$ into restoring the one you have. I still think you should be able to talk the price down unless the market for used bikes around there is really hot.