Hong Kong is famous for shopping. The stuff's there at all prices and in all qualities. Much of that you find in the street markets. When you go there, watch it, though: many items are actually cheaper in the regular shops. The fun lies in the browsing, of course.
Temple Street market even if listed in all tourist info well worth a visit—take your time
the photos are also from different markets all over Hong Kong
It's often hard to see where the market stops and the shops start
You can get anything on the market:
From famous Casio terrorist watch, reading glasses, binoculars—fish to look at and then, there's fish to eat. But that's another chapter: Food