Here is an iPhone case that lets you display text, graphics, animation, and more on the back of your smartphone. The LED Matrix Case has a blue display with 300 LEDs. It connects to your smartphone via Bluetooth. The case also has a 200 mAh battery.
This case has an on/off button to preserve battery. It is compatible with iPhone 6 and iPhone 6s. Costs under $50 at this time.[where to get yours]