Not only Isaan, I live nearby Kaeng Krachan,
and here in the local barbershop, it is also for 50 thb while I always give hundred.
If you come to the tourist place like Hua-hin they dare to charge 300 thb, and another even 400 thb, the most irritating thing is at these barbers they don't even listen how you want it cut.
That is why I have been going to the local barber here for years, and she is always done in 15 minutes, and never have to wait.