A cursory web search brings prices from $230 to $310, depending, apparently, on reticle. Start with replacement cost (including replacement with similar or better scopes,) discount that for age, condition, lack of packaging and paperwork, discontinued manufacture, etc. Then, perhaps, discount that for any friendship factor that may apply. I have faced the question only a couple of times and wound up making a gift of a decades old Weaver K4 (no accompanying goodies) and a Ruger Super Blackhawk (LNIB with all packaging and documentation.) In both cases the friendship factor far outweighed any cash value. On the flip side, I once paid fair market value for one shotgun, received roughly twice again that in other guns. YMMV