You should post this on the C&V valuation forum to get an idea of what it might be worth. You'll need to post some pics of the bike as well. The posters will give you an idea of what kind of work might be needed as well. At a bare minimum, you should replace the consumables (cables and cable housing, perhaps the tires as well). Ideally, you'd overhaul the bike as well. If that interests you, then this is a good bike to work on.

The 750s were Trek's top hybrids back in the day. They typically had a good quality steel frame and the parts were generally middling level. If you're interested in doing your own work, they're very solid bikes.