Hong Kong is a buyer-beware market. Name brands are sometimes fakes; that cheap jade you bought may actually be glass; and electronic goods may not work. To make things worse, the general practice is that goods are usually not returnable, and deposits paid are not refundable.
On a personal aside, I decided to buy a digital Sony camcorder and checked approximately 10 electronic stores, where I received price quotes ranging from HK$3,500 to HK$12,000 (US$455-US$1,560) for the exact same model. When I returned to the cheapest stores and asked to see the camcorder, however, I was told it was suddenly "out of stock," but the salesmen said they would be happy to show me a similar model for a slightly higher price. The problem is that there are so many models--including many that never make it to American markets--that it's difficult to know exactly what you're getting and what constitutes a fair price. In the end, I fell for the old bait-and-switch and bought a discontinued Sony camcorder at a higher price than what I would have paid for a newer model in the United States. I didn't do my homework before departing home (even checking the Sony website while in Hong Kong would have been a smart move), and I ended up paying for my mistake.
To be on the safe side, try to make your major purchases at HKTB member stores, which display the HKTB logo (a gold circle with black Chinese calligraphy in the middle and the words "Quality Tourism Services") on their storefronts. There are hundreds of member stores, all listed in a directory called A Guide to Quality Merchants that you can get free from the HKTB and at www.qtshk.com. Both give the names, addresses, and phone numbers of shops that sell everything from audio-video equipment to jewelry, clothing, optical goods, antiques, and custom-made clothing. HKTB member stores are required to give accurate information on the products they sell and to respond promptly to justified complaints. Of course, prices are often higher than at nonmember stores, but the payoff should be peace of mind and reassurance that you are paying a fair price. If you have any complaints against a member store, call the HKTB (tel. 852/2508 1234) multilingual hot line Monday to Friday between 8am and 6pm and on Saturday, Sunday, and public holidays between 9am and 5pm, or the Association of Better Business and Tourism Services at tel. 852/2806 2823.