OrderBorder offers the Tekkeon TekCharge Mobile Power Pack & Battery Charger, model no. MP1580, for $16.50 plus $5 for shipping. That's the lowest total price we could find by $5. It can be used to charge USB powered devices such as smartphones, iPhones, and MP3 players, as well as rechargeable batteries. (It requires four AA batteries, not included.) Offer expires February 8 at 2:59 am ET.