Decades ago I worked at the John Deere dealership in the parts department. Every JD part had a code printed on the packaging that, when decoded properly, told you how much the dealership paid JD for the part. It wasn't hard, just a quick glance and you could tell. The dealer markup on parts was astonishing. 300% was pretty normal and small items like bolts, nuts, and screws could be 1000%. Expensive parts > $500 were usually marked up < 100%. There was no set markup, the parts manager just marked the price up to where he thought people would still buy them.