I sold them a car a few years back and it went well. Their offer was a little lower than I would have taken from a private party, but not so low I wasn't willing to take it. The same goes for buying from them. I paid a few hundred more than I would have at a traditional dealer, but it was nice knowing the guy selling me the car didn't care if I bought that car or another in the parking lot. He was looking for faults during the test drive with me. They get a flat commission, so it makes no difference to them if they sell a $10k car or a $40k car. They just want a sale and a happy customer. The biggest thing about dealing with Carmax is doing your research prior. Know what the vehicle is worth because they won't move on their price. They make their money by selling a little high and buying a little low, so it's up to you to know if it's a little or a lot. You could be screwing yourself otherwise.