This is the folder I picked up:
Dahon Matrix (Chinese market) XRA643. It's basically an entry level hardtail trail/hybrid bike on slicks that folds. Closer to $5,000, though, but IMO life is too short for cheap bikes unless you're buying used, or buying something classic, like an Indian Raleigh or Chinese Flying Pigeon!
Bikes hold value a lot better than gadgets, too, and last a heck of a lot longer (usually), so spend the money and get something good. $4,000-5,000 is really as cheap as you want to go--there are a lot of very fancy $30,000+ bikes in people's homes here that only get ridden on cycle paths. lol