SF Planet via Amazon offers the Vena ZeusCase 3,000mAh iPhone 6 Battery Case in Black, model no. VN1141, for $59.99. At checkout, it drops to $25.99. With free shipping, that's the lowest total price we could find by $39. This MFI-certified charger features a built-in LED battery level indicator and protection from short circuiting and overheating.