Capacity: 550mAh, Weight: 36g, Colors: Standard Colors, Battery parameter: Gaoneng GNB 7.4V 550mAh 2S 80/160C, Continuous Discharge Rate: 80/160C, Size: 10*31*54mm.
Just check coupons out (with price alert and history). Let’s see what best price is ATM.
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 price update (UTC time):
Banggood
Banggood warehouse is located in China. I have no active coupons for you right now.
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!
Additional Banggood coupons: first page and second page
Old coupons (from the oldest to the newest): AFfbG10, BGBFAFF2019, BGCITYADS2019, BGVDay10%off, BGAFF10OFF, bGhOnEy10, BGdragonBoat, BGRCBC7, BGSS10%SW, BGRC902, BgoFErTaSchInA10, Parts8, BgcLuBofErtA10
(you can check these old coupons out, but these probably won’t work)
Price history and price alert
Do you need price history chart (for all/most countries) for Gaoneng GNB 7.4V 550mAh 2S 80/160C RC Battery JST? There we go. The lowest price was: $6.99.
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)).