well, you have to know your prices. the great thing about HK is that shopping is literally everywhere. i suggest to go into various trendy malls in TST or Mong Kok... you can find interesting things there. Often ahead of the fashion scene in USA. to me, fashion in asia is about 2 years ahead of what is popular in USA but maybe that is changing now with globalization? well anyway... the major malls are : causeway bay, landmark, festival walk, harbour city. if you like japanese clothing there is also a mall in TST called 'the one'. also IFC is a new mall... anyway here is a good list to get you started
Don't forget to factor in currency exchange. Most credit charge a hefty conversion fee. Ask your bank about their international ATM withdrawal fee, it may work out in your favor if the fee is low-just pull local currency from ATM so you don't have to carry cash all the time. Major retailers should also accept travelers check, could be another option. Last but not least is check how much luxury goods you can declare on custom form w/o getting taxed on. A family friend and her sister went on Asia/Europe shopping spree, got busted on withholding info on declaration form. Received a huge fine, it earn them a spot on warning list - 99% time they are subject to detail custom search
I am Canadian living in Hk. I am sorry to disappoint u but there is nothing cheap in china and Hk. If you are looking for small items you can probably find them cheaper on taobao.com and ship to ur hotel in china. Otherwise I find everything in Hk to be more expensive. I would say save your money and go to US!! Usually I carry an empty suitcase back home to Canada and make shipping trip to US.
The only store I actually bought something in HK is from the esprit outlet. I like the esprit collection pieces and have found a few cheaply in the outlet. If you like this brand you might want to check out the outlet in TST especially since esprit closed all stores in north America.