For short hair, how much should a salon charge for straightening?

My hair is about 6 inches at it's longest up top, three at it's shortest in the back and sides, and is thick; I went to a consultation at a salon and she said it would take about 3 1/2 hours, at $100 an hour plus conditioning, ect. So about $400 not including later maintanance. This seems astronomical, but I'm a guy and have never set foot in a salon... did she sense that and try to take advantage? What is an appropriate fee for shorter hair straightening?