Well, at least it's easy to identify. The Pepperoni fork, Beast of the East frame and black Deore LX group (with atypical thumb shifters) indicates that it is a 1993 model. If it needs a new chain it probably needs a new cassette too. The middle chainring is also looking quite worn. Unfortunately, vintage ATBs do not hold value well. In an average market, I'd value this at ~$150. Picture assist....