Beeebo-us via Amazon offers the Dodocool 4,200mAh USB Portable Solar Battery Pack for $28.58. Coupon code "NZKXGPSK" cuts it to $14.29. With free shipping, that's the lowest price we could find by $13. It can be charged via direct sunlight or the included micro USB cable. Features include a 1-amp USB charging port, rotatable 4-LED flashlight, and collapsible metal stand/hanging hook. Deal ends August 14.