I order nickle-and-dime things from them, things like LED keychain lights and uSD card readers.
I've also been impressed with some of the flashlights you can buy on there...aluminum tac-lights with the very latest LEDs for less than $20, often. Flashlights that make my Surefire E2 feel like using my cell-phone light.
The only expensive thing I tried to buy was a $30 electronic kitchen scale. It never showed up, and it's been 4 months or so now. Kind of soured me on them but what probably happened is it got stopped in customs and since I don't think DX declares things, just sends them through and hopes for the best, it's probably sitting on some custom's officer's kitchen counter.