I don't think the SE6 has been around for a while (probably 6 - 8 years), so I have no idea what it sold for new. If I had to guess, I'd say $1,400 - $1,500. Is that important, or are you looking for an idea of what a used one is worth today?
It would be the equivalent of the Rhino 172 today. The SE6 had a 65hp gearbox, a 10 gauge deck and sides and weighed about 750 pounds, very similar to the 172.