Tech-Rabbit via ebay.com has Mophie Juice Pack Helium Protective Battery Charger Case for iPhone 5, 5s, and iPhone SE on sale for $9.99.
Shipping is free.
The Mophie Juice Pack Helium Case is an ultra-thin, 1500mAh protective battery case made for the iPhone 5s/5. The case is engineered with edge to edge protection and gives your phone up to 80% more battery life while maintaining a sense of style and elegance. The enhanced forward ported acoustics redirects the audio to you opposed to the ground. Use the LED indicator to check battery levels before you head out and flip the standby switch when you’re ready to use the juice pack’s battery or when you need to recharge your iPhone while on-the-go. You can also simultaneously charge your iPhone and juice pack together with the included Micro-USB cable.