I recently replaced my oems and I made it clear to the store that taking the Dunlops had to be part of the deal. I got $80/ea for them (with 13k miles), and I did price the new ones before I sprung that on them.
This was a locally-owned business tho, I did find the Goodyear/Firestone/etc stores stated a "company policy" against buying/selling used tires.