You can find either used market for like 400-500 myr from high end brand.
For brand new, RM1k will get you decent one.

But there is a trick to find decent one. Follow my rule: 1-look underneath the seat, if it's just one big turn knob, it's probably not worth your time. 2- look for adjustable seat depth. if got none, don't even have to consider it. 3-arm rest: make sure the arm rest are not fused to the back of the chair. If you apply this rules, you will start seeing which chair is good and which is crap.