TOMO M4 DIY 4x 18650 Power Bank Black (Banggood, Aliexpress: Input: 5V / 1.2A, Output: 5V / 1A, 2A, Battery: 4x 18650 li-ion battery (not included) (the best price with coupon)).
Go down and check coupons out. Remember to check price history if it is available. Best price?
Aliexpress
There’re some similar (or not) items on Aliexpress
Click here to search by yourself. Here are coupons that you can use.
Latest coupon code price check (UTC time):
Banggood
Banggood warehouse is located in China.
Link: Banggood product page
1. ($14.41): fInbG2020
2. ($14.93): BGff2020
3. ($14.93): BGTORCH
apply code in your basket (cart) after clicking “Proceed to checkout”. Click to copy code and open shop.
Exclusive Allowance Coupons: https://bit.ly/3xWgD9k and https://couponsfromchina.com/short/5cd
Old coupons (from the oldest to the newest): 587ab1, e2bcea, linepayflt, EYBG, eybg, 502C6B, BGBFCR41
(there’s a little possibility that old coupon will work)
Other warehouses/versions
This item is available in 1 another warehouse/version!
1. China – TOMO M4 DIY 4x 18650 Power Bank White ($-3)
Price history and price alert
Here is price history (for all/most countries) for TOMO M4 DIY 4x 18650 Power Bank Black. The lowest price was: $8.99.
Price records source(s): Gearbest, Banggood
Click on image to enlarge. 
You can set price alert (for Banggood and Aliexpress (only if product name will be the same as on Banggood and I will post it on social media though, so it’s more like Banggood price alert)).