Amazon with Minghutech-US has the ESR Ultra-Compact 5000mah Qi2 Certified 15W MagSafe Power Bank (Black or White) for $17 - $6 off with coupon code BI2M4N4H at checkout = $11 with free shipping on $35+ or with Prime.

• Also available in Sky Blue, Lavender, or Titanium for $12 after code BI2M4N4H