Amazon has
RAVPower 10400mAh External Battery Pack $35.99 - $10 = $25.99.
Enter code HSBOUFVK for $25.99 at checkout
10400mAh of capacity. Charges all iPhone four to five times, a Galaxy S3 thrice, or an iPad / iPad 2 once.
Capacity: 10400mAh
Input: DC 5V / 1.5A (Standard Micro USB Port)
Output: DC 5V / 3.1A (2A+1A)
Warranty: 12 Months Warranty