RAVPower has one too. It's not much cheaper though. Hopefully USB type-C accessories will start coming down in price soon but for now you've gotta pay to play.
Qualcomm Quick Charge 2.0 + USB-C Port] RAVPower 20100mAh Portable Charger (Quick Charge Input & Output; Type-C Port)
http://smile.amazon.com/dp/B0156HCJQO
I also just found this one. It's half the capacity but also half the price. I am not familiar with this company but so far it appears to have good reviews so it might be worth a shot...
ORICO USB Portable External Battery, 10400mAh Power Bank, Qualcomm Certificated Quick Charger2.0 - Space Gray (Q1) (10400)
Link:
http://smile.amazon.com/dp/B018VK1TAU