I bought one of these a few weeks ago and I cannot tell you how awesome it is. I spend a lot of time in my Walmart taking pics and looking up things and my phone kept dying. Now I just plug in this handy-dandy battery pack when my phone is low and I get about 80% of my battery life back in about 20 minutes. Such a great deal!
The Rayovac PS60 Rechargeable Battery Pack is $17.97 at Walmart
Use the $3.00/1 coupon for the Rayovac PS60 Pack available under zipcode 76013