I used to use Pong, the queen from near Tukcom who moved down Pattaya Tai north side further than Friendship. He used to charge 60 then raised to 80. OK for the price but the guy started to get on my nerves.
My current cutter is in the building with KIss restaurant, 2nd road, corner of Pattaya North. There's a salon further down facing 2nd road. One lady is always there at night and they are open till 10. She's not the cheapest, 200 baht, and her English isn't as good as she thinks it is, so don't count on communicating well. However she will do something I value. If you ask her to she will cut your hair as she thinks is best based on the shape of your face, and you can also of course try to communicate general length. If you don't love that the first time, you then tell her what you want to change next time. Eventually you will probably like what she did (maybe 3 or 4 times max). Then tell her, and she will take a picture of you with your name, and the next time, after she looks at the picture she is amazingly good at replicating the look you like. That's better service than I ever got in the US. Cost is 200 includes shampoo/blowdry and half arsed head massage. She's also good at pedicures. She's not for everyone. For people who know exactly what you want, she probably will never really understand you. I agree that finding a decent haircut can be a challenge in Thailand. But it was also a challenge for me in the US.