For a limited time, and while supplies last, Sunvalleytek (via Amazon) has the RAVPower Luster 3,000mAh mobile charger for $8.49, shipped free for Amazon Prime subscribers. That's after applying coupon code BA5O7IZP at checkout.Normally $14.99, this compact, tube-shaped charger comes in your choice of colors. It can power pretty much any mobile device, though you'll need to supply the powered USB port to charge the stick itself. User reviews: a solid 4.5 stars out of 5 from some 1,300 buyers.