If you are looking for antiques, Best of Times (415 W 6th St, 310-514-3750) is a cavernous mall divided into sections for individual vendors to hawk their wares.
Threads of Time (446 W 6th St, 310-833-0568) has hard-to-find vintage apparel, while Cheap Vintage Inc has a huge inventory of bargain clothing and some notably racy mannequins in its window display.