@vanderson - No, you're not getting ripped off. In fact, I think my piano tuner charges the same thing. I've never completely understood what makes it so expensive, but I know it has to be able to withstand very high tensions. Perhaps it has to undergo some sort of special manufacturing process in order to allow it to withstand these high tensions?
The good news is that piano strings, unless they are very old, will usually do their job quite well. In the past three years of getting my piano tuned, I can only recall strings breaking on a couple of occasions, and my piano was manufactured in 1950. In general, I wouldn't be too intimidated about the price unless the strings on your piano are defective.