My step-mom charges about $5000 a room (depending on a few factors) in Arkansas. I would expect that to be a bit higher elsewhere.

That said, that involves her coming out and taking measurements, looking at the house, and really spending quite a bit of time with the customer. As stuff arrives she'll show back up and actually make sure it is installed correctly and make necessary adjustments.

This process is a bit less hands-on, and as such it can ONLY compete on price. You're paying less because you're getting less really.