You can haggle with shopkeepers to sell items. They’ll make an initial lowball offer, you can counter with something, they can counter it, eventually converging to a mutually agreed price. Sometimes refusing to go lower can convince the shopkeeper to accept the higher price; sometimes the shopkeeper will refuse to go higher. If you make an offer lower than their current offer, give them a YAFM ‘[shk] raises his/her eyebrow. “Deal.”’