"The Haircut" is a barber shop located in the Stanford Mall, not surprising, next to stanford. It's always packed with Stanford students looking for a simple haircut, which will run you around $15 after tip and taxes.
If you're not looking for something fancy, "The Haircut" is a good place for you to go. The barbers here (more like random women with cosmotology licenses) will chop your hair off whatever way you want: using scissors, that shaver thing--you name it.
Either way, it's a reasonable deal, and great if you're a student without a car since it's right next to Stanford University.