Last month Xiaomi was launched a 10400 mAh power bank for the price of 69 Yuan (around $11). Today, Xiaomi is rumored to launch a 5200mAh for only $5.
With the half capacity you can charge any smartphone or tab just fine. It looks like Xiaomi will offers a few different colors available for it power banks. We can be sure about this because of the leaked images.
We don't yet if the price is international or just for China's market.
[Source]