how to go to mongkok market from panda hotel using hong kong mtr? and how much?

There is no direct subway that can take you to the destination. You need to take a bus first then transfer to a subway. It's not a convenient way for you to choose. And the ticket fare is more expensive than the following way.
So you are suggested to take direct bus no. 33A at Wang Wo Tsai Street Tsuen Wan, and get off at Mongkok Market Complex. After arriving, walk to the market directly. The fare is 6.4 HKD per adult.