Living Social has the uNu Enerpak 5,000mAh USB Battery Pack in four colors for $19 (59 – 50% instant savings – 5 coupon) with Free Shipping for limited time. To get discount, use the coupon code: FREEDOM at checkout. Coupon expires July 5, 2013.

This portable battery back is compatible with iPhone 4/4S/5, Android Phones, Blackberrys, and most USB devices. It is able to re-charge almost any smartphone up to 2.5x while still managing to remain light-weight and completely portable.