For me, one of the highlights of last year's South By was shopping at the American Apparel Factory Flea Market sale. Thus, I was over the moon when I found out that they're doing it again this year:
Right now there are thousands of people confirmed on Facebook to come, but no worries. They bring in the inventory by the truck loads, and no matter what time you get there, you'll still be able to find something you love! Happy hipster digging!