Right now Amazon is offering Lepow Moonstone Series 3000mAh External Battery Pack for only $18.99 (reg $39.99)! Use the promo code 2JDA3K2Y to get additional $9.00 off (the code only works for the Apple Green option) and score this item for only $9.99! Plus you can get Free Shipping with Amazon Prime or on orders over $35.
*Make sure you double-check the price of the item when you add it to cart, as prices on Amazon tend to change often!