Price history, coupons and price alert are available on this page. What is best price?
Input: 5V / 1.2A, Output: 5V / 1A, 2A, Battery: 4x 18650 li-ion battery (not included)
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. ($14.93): BGTORCH
put item in your cart and apply coupon code there after clicking “Proceed to checkout”. Click to copy code and open shop)
Exclusive Allowance Coupons: https://bit.ly/3xWgD9k and https://couponsfromchina.com/short/5cd
Old coupons (from the oldest to the newest): 587ab1, e2bcea, linepayflt, EYBG, eybg, 502C6B, BGBFCR41
(these codes were not working in latest coupon update, but you can check them out anyway)
Other warehouses/versions
This item is available in 1 another warehouse/version!
1. China – TOMO M4 DIY 4x 18650 Power Bank White ($-3)
Price history and price alert
Do you need price history chart (for all/most countries) for TOMO M4 DIY 4x 18650 Power Bank Black? There we go.
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)).