25% tires and batteries, 50-75% everything else, with 50% typical for most parts. If I am stocking the item, I expect to charge at least 60% to offset the cost of keeping it on the shelf. Sometimes I can make a special purchase and bump the margins up a little to match what the item would normally sell for if purchased from a jobber. Ford COP coils are a good example. I can buy AC Delco or BWD for a good price, and use an average of the retail from my three local jobbers to set my pricing.