100% complete w/ minifigs (not pictured) - worth selling to BAM for $140 store credit?

Hi all, I found this Lego set in my bedroom closet at my parents house and was thinking of selling it. It’s 100% complete, minifigs in pristine condition with box and instructions. My local Bricks and Minifigs offered me $101 cash or $140 store credit. Does that seem like a fair offer? Not sure the etiquette at BAM but I didn’t try to haggle for a better offer, is that a thing? Should I go through the effort of selling it myself online? Thanks! ETA: I guess another question I have is why...