I've got a DX Racer chair & I like it, plus I've managed to make it last for a good few years now. There are many makes in the gamer chair sector like Noblechairs, Need for Seat, AK Racing, Omega, Corsair & many more. If you can try them out in person it really helps to get the right one.
The MARKUS office chair is nice and suggested by a lot of people & there will be ROG gaming chairs available from October that I've seen reported, right down to £50.00
I've had RH Logic 400 office chairs for the kids, but these are super expensive if you get them brand new and can be had second hand in good condition. But you want something that's going to be able to potentially be used for hours and you want to be as comfortable as possible, as I've had some terrible cheap chairs in the past and they can become very uncomfortable.