Sunvalleytek via Amazon offers the RAVPower 5,600mAh External Backup Battery Pack, model no. RP-PB03E, for $25.99. Coupon code "C4VIOZCK" drops it to $15. With free shipping, that's $1 under our mention from two weeks ago and the lowest total price we've seen. It features a built-in flashlight, auto-off, and compatibility with a wide range of devices (including the iPad, iPhone, and Android phones).