Qistina express is a bus company that has busses that go around Malaysia and even Singapore. I took this bus for the first time to go to singapore for SGD28(I used paypal to make my purchase), and took the bus from BTS. It’s really fast and super convenient. Not all busses offer online ticket purchase. I think it’s a very smart and efficient way to get busses without having to drive all the way to the teminal. The busses are also fairly clean!