cheapest would be salvaged/used steppers. there's a bunch of auctions out there for these, most were pulled from large scale business printers/plotters.
Peqo The second one is under spec. The first one may work but it is pretty expensive with shipping. Try these from sparkfun. [www.sparkfun.com]
68 oz-in, 400 steps per rev for $17 and it is from a reputable company too!
