LoHi via Amazon offers the LoHi 7,000mAh Battery Case for iPhone 8 Plus / 7 Plus / 6s Plus / 6 Plus for $39.99. Coupon code "AVZQH662" cuts it to $24.97. With free shipping, that's the lowest price we could find by $20. It can hold two full charges, features LED indicators, and adds 0.36" thickness to your iPhone. Deal ends December 1.