Ending today, Newegg offers the refurbished Digital2 4,400mAh Portable Battery in Metallic Blue, Metallic Gold, Metallic Purple, Blue, or Purple for $11. This $11 mail-in rebate cuts it to $0. With $1.99 for shipping, that's tied with our mention from two weeks ago as $15 under the best price we could find for a new unit. It includes a microUSB to USB cable and features an LED battery status indicator.
A 90-day warranty applies, but it is unclear who backs it.