Amazon has the Mpow 12000mAh External Battery Portable Charger Power Bank for $38.99. When you enter the coupon code: PB31MPOW at checkout, it drops the total to only $29.99 with free shipping. That’s $36 off the list price and the lowest it’s ever been.
It features a capacity of 12000mAh and it’s constructed out of an aluminum alloy that keeps it very lightweight. It has two USB ports that lets you charge two devices simultaneously, and it is one of the lightest and thinnest power banks out there.