Carmax and all the other dealers dont go off of KBB. KBB is so useless no one is never going to get KBB for most of the cars out there. kbb is way higher than the used car market prices reflect. Carmax and dealers go off of what is called black book value and you can look this up online. They need to be able to make money on buying your car, no business in their right mind would offer a price that the car is going for. but carmax pricing is a good way to see a bottom price range.. like at least you'll get $x and carmax will give you a check right then and there. So whatever you sell from private party should be a good amount higher than carmax's offer.