We have one of these we bought new for about $3500 at a spa show 3 years ago (in 2004). So the guy should be discounting it more than $300. If I was getting rid of mine, $2000 would probably be acceptable, maybe even less if I really wanted it gone.
Plus it will cost you about $400 to get an electrician to wire it up at your house unless you already have a spot for it that is prewired.