Aukey PB-N73S 10000mAh 18W PD USB-C Slim Power Bank $14 at Amazon

Amazon has the Aukey 10000mAh 18W PD 3.0 USB-C Slim Power Bank with Quick Charge 3.0 (PB-N73S) for $19 – 28% off with coupon code Z89F9DBE at final checkout =  $14 with free shipping on $25+ or with Prime.