Go to the new Fu De second hand market, near the new South Bus Station. (A couple blocks south of the south train station.) Easiest way to get there: bus #127, caught somewhere along Long Quan Lou or Yi-er-yi Street. If you head south on Qing Nian Rd., keep going south after it turns in Nan Ba Rd., and go through the big clover leaf. It should be on your right, as you head south. It more or less replaces the 2d hand market that used to be on Bai Yun Rd. Lots of 2d hand bikes, computers, etc., etc.