Just like medical students learn to be doctors on patients, cosmetologists and the like need to learn their craft as well. This means that those who do not have the money, or simply do not care about the end result, allow students to practice on their hair. I did this once, and truthfully, the end result was ok. It likely could have been worse, and certainly could have been better. However, because I knew what I was in for ahead of time I did not feel bad. The student was very nice and did a great job of engaging me while she was cutting.
Bottom Line: Go here if strapped for cash, or if you just want to let a student practice on your difficult cowlick.