LOL you dont haggle in Hong Kong, Hong Kong isnt like china, where you can haggle your way down from 500 dollars RMB to 50 RMB. everything there has a fixed price.
Kwong wah Street is a good bet, also check out sham shui po, as well as stores on Castle peak road like Ehobby etc.
Also UN company in Wanchai.
Theres also a bunch of other small stores everywhere like armorytechairsoft in Sai Wan Ho
Also be sure to check out Lankwai Fong for some good partying time there