For most of the markets, your best bet is to go in the morning (most places open at 10am), armed with your best haggling skills and a secure grasp of your Chinese numbers.
The quality is generally pretty dismal, but for throwaway fashion (with little regard for the environment) you can't go wrong.
Prices are pretty reasonable and most of the bags are in fact real leather (you can decide how to feel about this) and fairly well made.
It's not as cheap as the other markets, but still better than buying the originals.
Qingping Medicine Market Guangzhou's biggest medicinal market is like a look back at the old apothecaries of yesteryear, so long as you can handle the smell of all those dried seahorse and hedgehog hides.
Selling stuff that isn't quite medicine in massive quantities, we doubt you'd like to try any of it, but it'll make for some nice photos to show everyone back home.