Toni & Guy Academy
http://toniandguy.com.hk/education(model-1).html
The price for a haircut is only 50HKD, but I got it for free since I was asked by the stylist to be a model for his graduation presentation. Very happy with the haircut, so much better than all the full-priced ones I had before. When I was getting the cut, another girl came and asked me if I could be a model for her coloring excercise. Since I was worried about the effect of hair dye on fetus, I declined. But it was very tempting since she wanted to dye my hair red.

I may try this other one next time, although I am a little chicken about my limited Cantonese, but I guess it shouldn't be a huge problem!
Beyond the Fringe
http://www.btfhair.com/model_service.htm