Newegg offers the Vantec Power Gem 3,500 mAh Rechargeable External Battery Pack in White (pictured) or Pink for $14.99. A $5 mail-in rebate cuts the price to $9.99. With free shipping, that's the lowest total price we could find by $32. It features two USB ports and measures 4.45" x 2.32" x 0.59". Rebate ends December 3.