Basically copy coupon, view price history or create e-mail price alert. Best price?
Colors: Standard Colors, Weight: 109.6g, Continuous Discharge Rate: 80C, Capacity: 550mAh, Size: 31*31*61mm, Plug: XT30 Plug
Aliexpress
There’re some similar (or not) items on Aliexpress
Click here to search by yourself. Here are coupons that you can use.
Latest price update (UTC time):
Banggood
Banggood warehouse is located in China. So I have checked for active coupons (all category coupons and old ones), but there was no working coupon in Banggood.
Link: Banggood product page
Price: $-3
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 and https://couponsfromchina.com/short/5cd
Old coupons (from the oldest to the newest): BGandy6, Charger12, affbg10, AFfbG10, 0e7f33, FBCOUPON1, BGAFF10OFF, BGCuponation10, BGBCSpring1, BGDAVIS
(probably won’t work, but you can try them out)
Price history and price alert
Check out price history chart (for all/most countries) for Gaoneng GNB 22.2V 550mAh 80C 6S RC Battery XT30.
Price records source(s): 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)).