Forget about Mongkok. Forget about "Woman Street". Go straight to the source baby!
Take subway to Lai Chi Kok station, follow the direction to "Hong Kong Textile Industrial Building". There you will find all kinds of trendy japanese/korean style clothings. CHEAP. The lined wool jacket in the middle is only $100 HKD. Approximately $15USD. This is just part of the loot. The others are in the basket waiting for the next laundry round. Most of the stuff there are around $5US. But some of them only accept wholesale request, so ask before you grab them. Most of the time when you see a price tag, it means they are ok for retail. If you don't see a price tag so you have to ask, chances are they are for wholesale inquiries only.
Tips: Bring a wheeled suitcase. It will make your life much easier. Otherwise you will have to drag 2 huge plastic bags full of clothings back like me. T-T In fact it doesn't look weird if you are pulling a suitcase around there. Lots of people are doing that.
Also, bring cash.
Coming home.
First, one must acquire the plants, and devise a way to stuff them into one's car. These big babies came from a wholesale nursery in the valley. They're double the size and half the price for the same plants I can buy in my local nursery.