Groupon offers the uNu Apple-Certified DX Protective Battery Case for iPhone 5/5s in Matte Black, Glossy White, or Red for $49.99 with free shipping. That's tied with last month's mention and the lowest total price we could find by $30. The 2,300mAh battery purports to provide up to a 100% battery boost and features a microUSB port. Deal ends November 12 at 1 am ET.