Aliexpress
There’re some similar items on Aliexpress in my database. There may be some other items though.
| Image | Product (link) | Price | Coupons |
|---|---|---|---|
 |
2x LiitoKala NCR18650B 3.7V 3400mAh 18650 Battery | 6.94 USD | – |
More on Aliexpress… Here are coupons that you can use.
Latest coupon and price update (UTC):
Banggood
Banggood warehouse is located in China.
Link: Banggood product page
Coupon (17.67 USD): BGAlerabat15
Coupon (17.67 USD): BGtorch7
(CouponsFromChina.com tip: 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
Old coupons (from the oldest to the newest): BCNLXK, BGBFCR41, bGhOnEy10, BgcLuBofErtA10, BGFLS15, BGAFF10OFF, BGCuponation10, BG10OFFAFF, BGwhielabel, 4BLF, BG10OFFAFF1, BGFLBA, BANGGOODSD
(you can check these old coupons out, but these probably won’t work)
Price history and price alert
Here is price history (for all/most countries) for 2x NCR18650B 3400mAH 3.7 V Battery.
Price records source(s): Banggood
Click on image to enlarge. 
You can set price alert (for Banggood).