The Garment District is across the street from my office. If you were going during a lunchtime, I might join you.

tpau, below, is slightly conflating 2 stores in the same building, which both sell used clothes. Upstairs is Garment District, which is actually organized by clothing type and can be cheap, cheap (I found a Pierre Cardin tuxedo jacket for $15, but it was much too big for me). Downstairs is Dollar-A-Pound, which sells clothing by weight (I think it's actually $1.50/lb. these days).