Amazon is offering the RAVPower 5600mAh External Battery Charge / Power Bank for a good price.

This works on any smartphone or tablet
This adds 6 extra hours for the iPad

Step 1
Go to Amazon and add the item to your cart for $25.99 shipped

Step 2
Use coupon code 3JDJS6HW to get $9.50 off

Final Price : $16.49 Shipped