As above ... it is all so subjective and depends on condition. Being an S adds something but the lack of a sight detracts from price. Any idea how well it shoots? This may not be a deciding factor but knowing that it runs at maybe 10 is a good sales point. At auctions I have seen ordinary i.e. non-S Airsporters go for anything from £60 - £150 or more plus commission at about 25%. But rough looking ones, marked stock, a few scratches, maybe bluing rubbed off, trigger block with blacking chipped etc are at the low end.
Cheers, Phil