I am monitoring price for 1500mAh 4S and it is for 26.9 USD now (in Banggood). You can create price alert here, copy coupons and view price history. Let’s see what best price is ATM.
Latest price update (UTC time):
Banggood (26.90 USD)
Banggood warehouse is located in China. There is no active coupon in my database right now (for Banggood). Low/high price? Well, this price is higher than average price (19.23 USD)
Link: Banggood product page
Price: 26.9 USD
Exclusive Allowance Coupons: https://bit.ly/3xWgD9k
Old coupons (from the oldest to the newest): BG148V, AFfbG10, BGWKBA, BG148CG, 502C6B, BGBFLIPO, BGCHNLG, 0e7f33, BGPLKM4, BGBD2F, FBCOUPON1
(these codes were not working in latest coupon update, but you can check them out anyway)
Aliexpress
Here are coupons that you can use.
Price history and price alert
Do you need price history chart (for all/most countries) for CNHL G+ PLUS 14.8V 1500mAh 4S 100C RC Battery? There we go.
Price records source(s): Banggood
Click on image to enlarge. 
You can set price alert (for Banggood).