you asked about not knowing the year, here's a quick guide. the first one is 2012 and older. the second image is 2013 and newer.
the pre-2013 models had a great seat, but no adjustment, and they had a 'raised' cutting board hatch between your knees. the newer models have a flush hatch (commonly referred to now as the 'square hatch'), and this model is more conducive to standing to fish--which you will do a whole lot more than you think.
fair market value varies with region. there are some bargains out there, but not many. they get scooped up pretty quick. the great thing about buying a used Ferrari, the resale is fantastic. if you get a fair deal, plan on getting 90%+ of your money back out of it.
and for what its worth, each Hobie i have sold used, i pony up to have it serviced at my local shop so the new owner has a great boat to start out with. it costs me like 60 bucks. use this as a bargaining chip? and you'll know from the local dealer if there is anything you need to know.

