Aliexpress
Here are coupons that you can use.
Latest coupon and price update (UTC):
Banggood
Banggood warehouse is located in China. I have no active coupons for you right now.
Link: Banggood product page
Price: -3 USD
It looks like this item is out of stock in Banggood. If you found it then please send me the link. I will replace it.
Click here to search on Banggood!
Exclusive Allowance Coupons: https://bit.ly/3xWgD9k
Old coupons (from the oldest to the newest): e2bcea, CMB3, BCNLXK, BGBFCR41, fInbG2020, BGff2020, BGAFF10OFF, BGCuponation10, 4BLF, BGHONEY2110, BG10OFFAFF, BGwhielabel, BG10OFFAFF1, BGFLBA, BANGGOODSD, BGTorch4
(you can check these old coupons out, but these probably won’t work)
Price history and price alert
Price history (for all/most countries) for 2x Keeppower P1835C2 IMR18350 1200mAh 3.7V 10A Battery With Box is here.
Price records source(s): Banggood
Click on image to enlarge. 
You can set price alert (for Banggood).