Value is highly subjective. The pallets full of the Nagants from five plus years back have been pretty well picked through. Good ones, with the lanyard, screwdriver, cleaning rod, and holster, are not $69 from the surplus dealers anymore. Most places, $100 gets you one with a dark bore now. Another factor - a commercially imported one will be stamped - CAI did so in a very obvious place - on the sideplate. I/O did so in a more appropriate spot - under the barrel - I'd pay more for that - more for the accessories mentioned, too. No import mark and a decent bright bore - likely a decent DA pull that doesn't take both trigger fingers to pull - and that $150 price would seem a bargain.
In the final analysis, only you can determine 'value'. If it's a decent example - and you enjoy your purchase - you'll quickly forget the price you paid. If it's a turkey - and you paid half of that amount - you'll recall every cent paid - and not in a good way. Perhaps, if it is still to your liking, you could suggest that the trigger group could be mismatched to the gun. Literally hand made - and with serialized parts - they occassionally got mismatched in their re-arsenalling. Certainly, you have some barter rationale. Of course, there is always the thought of just what else can you buy these days for $149?
Merry Christmas!
John
PS See if they have the Serbian made commercial 'Hot Shot' 1895 Nagant ammo for it - maybe throwing in a box will sweeten the deal ($26-$35/box).