EasyAcc.A Store via Amazon offers Prime members the EasyAcc U-Bright 9,000mAh Power Bank for Mobile Devices for $29.99. Coupon code "CEASYACC" cuts it to $23.99. With free shipping, that's $36 off list and the lowest total price we could find. (Non-members can spend $35 to qualify for free shipping; otherwise, it adds $5.39.) This power bank features a built-in LED flashlight and dual USB output. It is compatible with a range of smartphone and tablet devices.