Apple has lowered prices on its refurbished iPads. For example, the 16 GB iPad2 with WiFi only is now $319. First generation iPads, only $279. Refurbished products have a one year warranty and new battery. The refurbs I've purchased from Apple were indistinguishable from new. (They do come in a plain brown box.)
http://store.apple.com/us/browse/home/specialdeals/ipad
http://store.apple.com/us/browse/home/specialdeals/ipad