Battery capacity: 1250mAh, 3000-time cycle life, Constant voltage: 1.5V.
Just check coupons out (with price alert and history). Best price?
Aliexpress
There’re some similar (or not) items on Aliexpress
You can use link bot to get even lower price:
Click here to search by yourself. Here are coupons that you can use.
Latest coupon and price update (UTC):
Banggood
Banggood warehouse is located in China.
Link: Banggood product page
1. ($14.45): BGTT10
2. ($14.45): BGdragonBoat
3. ($14.45): bGhOnEy10
4. ($14.45): BGRCBC7
5. ($14.45): BGAFF10OFF
apply code in your basket (cart) after clicking “Proceed to checkout”. Click to copy code and open shop.
Exclusive Allowance Coupons: https://bit.ly/3xWgD9k and https://couponsfromchina.com/short/i1u
Old coupons (from the oldest to the newest): Charger12, AFfbG10, 0e7f33, BGHU635, BG10BC, FBCOUPON1, BGBC1, BGSS10%SW, bgshOOp10, BGRC902
(these codes were not working in latest coupon update, but you can check them out anyway)
Other warehouses/versions
This item is available in 1 another warehouse/version!
1. China – 4x ZNTER USB Charging 1250mAh AA Battery ($-3)
Price history and price alert
Do you need price history chart (for all/most countries) for 2x ZNTER USB Charging 1250mAh AA Battery? There we go. The lowest price was: $4.89.
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)).