Picked up some of these off Ebay for about $18, came with 3 large and 3 small clothes.
They don't Absorb water as well as advertised, they can hold a suprising amount of water, but they take several passes over a watered surface to get it all, which was kind of dissapointing.[>:]
BUT, they do suck up dirt and crap thats on your paint very well, even the stuff thats stuck there after a quick wash.

After a run with Zorbeez the Stealth Stang is looking good.

So if you have a few extra bucks, try them out. 7/10 for me.