There are some honest gun stores out there ...that deal in used guns / and some of them keep their profit margins fair ...and offer respectable deals to sellers and buyers ...at least in my area.
And sure / everyone has to make a buck in the deal - so you might be able to sell it for more as a personal sale....but putting it on consignment ( where the store owner might take 10 - 20% ) can expose the gun to hundreds of buyers - that you might not be able to reach otherwise. Store owner has to do all the transfer paperwork, etc as well ...and he deserves something for all that as well.
In this case / if he knows what he would get for a trade in value ....my thought is it would just be an easy way to make his buddy a deal - and for him not to get hurt financially in the deal. But he should add the sales tax to the value ( say 10% in my area ) ...because if he were to trade the shotgun in / he would put the value toward his handgun ...and not pay sales tax on that trade in value -- only the remaining value on the handgun.
But come on now Donkee ...you know ( deep down in your heart ..that 1911's Rule !!! ) .......
( Just yanking your chain man ....) ....