..... Drum roll please ...... Lol.
That's a tough question to answer.
I suppose the price of a saw would be dictated by its condition in both appearance and mechanical capability. Given a saw of that vintage has been discontinued for a good many years, it is a bit of a sellers marker, and being at the right place at the right time. I unfortunately am at the mercy of the seller, and would be giving a price based off selling history on eBay and maybe AS. Unfortunately supply and demand will likely inflate a sellers asking price to the point of "how bad do you want it, and how much are you willing to pay to get it?"
Then of course there is the seller and his honesty, or lack thereof in being truthful about exactly what it is he is selling.
With that said, I missed a nearly mint SP800 a month or so ago that went for $355.00 and am still kicking myself, there was one sold a couple weeks back for $299.00 and there is one listed right now for $120.00 and they were all pretty rough.
I think if the right opportunity comes up, I would spend the $, but am not going to rush.
What have you got for sale?