ECS prices seem to be very inconsistent. They have an idea of the 'value' and stick with it. Some stuff is super cheap and some stuff is stupid - like that D90 pricing when the they were selling the D90 body new for just $100 more after rebate.
They are also very reluctant to haggle - seeming to ignore that the markup on second-hand goods is quite high. I always come away from there with the feeling that they don't care if they make a sale or not.