On Amazon right now you can get this Powerbag Instant Messenger Laptop Bag with Battery for Charging Smartphones, Tablets and eReaders (RFAP-0015P) for only $49.99. This is a 72% savings and shipping is free! Here is a little bit of info about this great bag:
Built-in charging system and removable 6000mAh battery to charge your favorite USB power devices
Built-in Apple, Micro-USB, Mini-USB connectors and a USB port
External one-touch battery level indication
Included wall adapter charges Powerbag and any connected devices inside easily via the external waterproof charging port
Quick-access charging pockets
Note: Amazon prices and promotions can change at any time. The price(s) listed in this post is/are subject to change.