HYPE Power Shell 13800mAh iPad Battery Case - for the iPad 2 and 3 - Black for $74.99 + free shipping
Power Shell Double the battery life of your iPad. Never be without power again. Snap-and-go case adds minimal bulk and provides easy access to all cameras, ports and buttons. With your iPad securely inside the Power Shell, your device measures only 0.5"thick. With a durable exterior and a micro-suede interior, you can ensure your device stays protected.
•Double the life of your ipad
•LED power indicator lights
•ON/OFF power switch
•Rechargeble lithium-ion batter
$95 for a used one on Amazon