The Doctor wrote:
I am travelling to Hong Kong around December. Given that a lot of things
can
bought via the Internet these days. Are they anything worth picking up
in HK? My budget is rather limited.

If you want real bargains, head across the border to Shenzhen.
There are some decent shops, and don't be surprised to see bikes from
$20 to $5000 in the same shop!
Folding bikes can be had for one third of the Australian price.
As Artoi said, the best bargains are the chinese-made products,
but this includes foreign-branded ones, e.g. Shimano, Dahon.