hi chloe
i usually go to Causeway Bay cos I like things at Island Beverly (diagonal to SOGO) and another complex next Eu Yan Sang. These complexes have HK designers' own labels which u can't find elsewhere. There's also a new shopping complex called Mongkok something. It sells a lot of handbags. Essentially, brands at Times Square can be found in S'pore. I normally head straight to Joyce Beauty to grab beauty products.
As for those shopping malls at Taikoo, Admiralty, Central, they are too expensive, and most of them could be found in Singapore too.
If u r looking for cheap fashion, TsimShaTsui will be the place for u. A lot of shops carry funky street apparels, some are factory overruns and seconds, some are local designs made in China. If u don't mind quality, 'In and Out' Fashion sells affordable things like those in our THIS FASHION. Are u into European labels? U might get limited stock in some shops at TsimShaTsui too.
Festival Walk at Kowloon Tong MTR is also highly recommended by me. But most of the brands, again, can be found in S'pore.
If u hv the time to cross the border to Shenzhen, things are a fraction cheaper than HK's. But the experience is less desirable than that in HK. I'm always thrilled to walk the bustling streets of HK, even though I can buy the same brands in S'pore!