Many many of those places on price.com aren't so much real shops but dealers of various sorts operating out of small offices on upper floors of commercial buildings you'll have trouble finding if you're not familiar with Hong Kong.
They often deal in parallel imports, demos, open-box goods and such.
And the listed prices, even when shown as updated yesterday, can't always be taken as reliable. More importantly, the listings often show goods that aren't actually in stock. You've always got to call and ask about availability first. Sometimes there'll be availability, but you'll have to pay first and wait a few days for the stock to arrive.
Warranty is often just the shop's warranty.
Unless you're willing to save some money by taking some risk, I'd suggest steering clear of these places. Though they're probably a better bet than buying in TST!