Again, ninety-nine percent of the stock will be junk, but I've picked up nifty coffee mugs, shelves, mirrors and racks for next to nothing. If you've got a few supplies for restoration handy, take a peek at the furniture. Even if it's ugly, chipped or peeling, if a piece is solid you can refinish it. Knobs, handles, and other hardware are simple enough to change, and can make a world of difference. I've seen some lovely furniture that was rescued in such a manner.
Check out the shoes
As with all clothing, check for structural integrity and/or any hidden nastiness. Most places will at least spray their shoes with disinfectant, but you can't count on it. If you're OCD to the core, you may want to bring some hand sanitizer or wipes; or, if you are expecting to try on shoes, stuff a pair of socks into your purse. You'll have the best luck if your feet are between sizes 6-9 (women's) and 9-12 (men’s), naturally, but I've seen some fantastic offerings for bigger and smaller tootsies.
Last of all, be patient
Sifting through crap takes time, and there's always the chance you'll strike out no matter how closely you look. Hidden treasures like 1970s russet leather jackets and patent leather Cobbie shoes do not lurk within every single Goodwill or Salvation Army. Success may take time, and it may take persistence.
So go ahead and make a day of it if you can pull a group together -- consider it a city-wide tour of cheapness. It’s a fun, inexpensive way to expand your wardrobe horizons and take a trip down fashion memory lane.