The main valve in my bathroom was leaking and then jammed when i shut it so I got a contractor/plumber via recommend.my to inspect.

Not sure if its called a shut off valve or stopcock valve (or if the terms are interchangeable) but the valve and some of the piping would have to be replaced. Since its a main valve connected to the wall, some hacking would also be necessary. Contractor quoted me RM 800 for the entire job.

Is this pricing OK? Did not expect it to be this high but I guess the drilling probably takes a bit of time and effort..

How to tell you cheap or expensive without knowing what your exact materials used or location/replacement/job scope difficulties are?

too expensive, ask him to give you a detail itemize bill invoice