45% is about average in most barber shops but the owner can, and will, charge you for chair rental and a percentage of your total sales, weekly, monthly, etc.
Do barbers keep all the money?
Probably most barber shops rent a barber a space (booth rental) and the barber pays a certain amount to the shop owner on a weekly basis, fees vary greatly. In the last case, the barber handles their own money and simply pays rent.