DrHotDeal via eBay offers this Ultra Thin 20,000mAh Portable Battery Pack in several colors (Gold pictured) for $9.99 with free shipping. Outside of eBay, that's $20 off and the lowest price we could find, although we saw it for a buck less a month ago. It includes a charging cable and has aluminum casing.
Dollar stores lure us in with their rock-bottom prices, but not everything is a bargain. We suggest you steer clear of these items.