The tour bus operator that I use for new tires, Burke Christian Tours, Denver, NC, is the only place I've been to that's given me a credit for my old tire's. They do it by date code, they don't give much for a tire that's 5 years or older. Less than 5 years will bring a good credit. I don't have my receipt in front of my so I can't tell you exactly how much. IIRC it was around $100 per old tire - don't quote me on that till I verify it.