I have a red Powerebag for sale for the low price of $100. This bag retails for $140. If your not familiar with this badass bag I have a link below. The one I have is red and still has all the original tags brand new!
http://www.mypowerbag.com/backpacks/backpack.html
Basically it charges your phone, ipad, anything with a USB port all from the backpack.