We don't really have vintage or antiques flea markets in Hong Kong. The really nice stuff was either stolen by the Europeans or already live in shops that sell them for rather high prices. The stuff you get on Cat Street is hit or miss. They mostly cater to tourists, but I do pass by once in a while to take a look. You never know what kind of gem you might dig up, but it really takes a lot of patience and a good eye.
A bit of haggling is to be expected, but please do be polite about it. I often witness tourists being complete assholes and speaking rudely to the stall owners, and sometimes, even cursing them out. It's not that fucking important, Jesus. If you can't afford it, take the loss and move the fuck on!
Anyway I bought this security guard cap for HKD60 on Cat Street. Love it, I wear it as much as possible.
And my friend bought this antique puppet for (I think) HKD400, but he ended up giving it to me because I don't mind it when inanimate objects follow you around the room with their eyes.