How much does knockdown texture cost to put on a ceiling?

I just had a guy put up knockdown texture on the ceiling of practically my whole house. The house is about 1300 sq. ft., so taking out the bathrooms brings it down to maybe 1200 sq. ft.? He charged $1,100.

However, this included taking down acoustical "popcorn" in the hallway, and patching the ceiling throughout the house, which had quite a few gouges and cracks when the old popcorn was removed.

I still am convinced that I may have over paid, but whatever. I think if you have ceilings that are fully ready to go, it should cost you $500-$600 for about 1200 sq. ft. (that's my guess anyway) Basically $0.50 per sq. ft. It should only take the guy (with a helper if needed) about 2-3 hours.

Sounds like this guy should have done it himself since he is so knowledgeable. Don't know why he would have called a professional, MORON!