Originally Posted by dtsm

Sham Sui Po is the place to go but as HKT says, you need to know your stuff.

Another option is to take a train up to Shenzhen - this is the mobile phone capital of the world. There are numerous places but one that I recomend visiting:

4A-043B, 4/F
Hua Jiang North Rd.

Literally 4 floors with hundreds of counters of phones - all local Chinese, all reasonable quality and price.