eBay has the New Trent Travelpak PLUS External Charger for Smartphones & Tablets for only $19 shipped. It’s originally listed for $90 and Amazon sells it for $42 currently, but we have never seen it this low.
It features a dual USB port and an external battery charger (7000mAh capacity) with built-in foldable AC Chargers. It can charge the iPhone 5 four full times, and the same with the Galaxy S3. Not to mention that it’s compact, stylish, and handy for any traveller
For an extra $5 you can pick up a much bigger New Trent: IMP99D External Battery Charger for Smartphones and Tablets (below) for $23.95 with free shipping also from ebay. It features 11200mAh of power with Dual 5V/3A Micro USB input 5X iphone battery. Frankly it also looks nicer.