Anko 5000mAh Dual USB-A Output Power Bank, White $5 (Was $15) + Delivery ($0 OnePass/ $65 Order) @ Kmart

Not a whole lot of juice, but $1/Ah is not a bad price.

Material:

• Main housing: Acrylonitrile butadiene styrene (ABS)
• Battery: Lithium-ion polymer
• Printed circuit board assembly (PCBA)
• Foam
• Electronic silicone

Dimensions/Size:

• Power bank: 9.8cm (L) x 6.45cm (H) x 1.6cm (W)
• Charging cable: 30cm (L)

Power source:

• Micro USB & USB-C input: DC 5V/2A (max.)
• Dual USB-A output: DC 5V/2A (max.) (combined output from two ports)
• Battery information: 5000mAh/18.5Wh