The Palm Beach Goodwill is the best place to get designer name clothes, purses, and shoes at low prices. Many of the people on palm beach give away items that were never even worn or were only worn once. I always could find clothes in perfect condition at this Goodwill to stock my closet with. One time I even found a floor length royal blue sequined evening gown here (from cache, retail $300) and it was a steal at $75.
This store carries a number of evening gowns, some housewares and art, and jewelry and accessories as well as clothing. Every day they have a percentage discount on a different type of colored clothing tag, they'll usually let you know when you walk in. It's definitely worth a stop after you check out Worth Avenue and can't afford anything. (Or maybe before so you can get the designer shades first.)