Sunvalleytek via Amazon offers the RAVPower Element 10,400mAh Portable Battery Pack in Black or White, model no. RP-PB07, for $21.99. Coupon code "R2X84A3Z" cuts the price to $13.99. Plus, Prime members receive free shipping. (Non-members can spend $49 or more to qualify for free shipping; otherwise, shipping adds $6.37.) That's the lowest total price we could find by $12. It features dual USB output, an LED status bar, and includes one Micro USB cable.