This loan arrangement also works to the customer's advantage in many situations as the book values of used cars don't always align with realistic prices.

I bought an excellent condition Honda S2000 from CarMax about a decade ago. If I didn't have $20k in cash, it never would have happened outside of a CarMax. The car was absolutely worth that value, but the book valuations were much less. I could have possibly purchased an older car with more miles a lot cheaper, but the CarMax quality was actually a great driver for a vehicle that could have been treated poorly in its past life. Currently, the book value for my car is around $15k, but nobody's going to sell you a similar car anywhere near that cheap.

Bottom line: CarMax tends to buy lower mileage vehicles than other used car sources, and the vehicles tend to be in good order. It's always still worth having the vehicle checked while you are within their guarantee window.

Their process is easy, and I'd use them again.