I haven't been there, but I remember some TV news puff pieces on getting cheap haircuts at beauty schools. One around San Francisco was the Vidal Sassoon Academy. Now would anyone here trust their hair to a student?
In a similar vein, we have a local optometry school with a clinic. I could have chosen to get exams there with my vision plan, or just pay a fee comparable to any other place. I understand that they use it to train students, but that a licensed optometrist (or possibly an ophthalmologist) will supervise the exams and double check the results. However, it's not specifically cutting anyone's hair though. I was told that they might actually take longer, but the quality of the exams is equivalent, especially with highly experienced personnel supervising.