It's basically trade value that Carmax offers--they make it seem like you will get more than what you would get if you were to trade in at the dealer you are buying your car from. I have the exact same as you '01 and 98K miles--I have Sport, Premium, Climate and looks only a few years old. Best thing is to do Autotrader (you could get probably around $11K I bet). Problem is on a trade-in on cars with 100K miles dealers really don't care they will auction the car off--they won't give you too much for them.