Aliexpress
Here are coupons that you can use.
Latest coupon and price update (UTC):
Banggood
Banggood warehouse is located in China. Too bad there’s no coupon right now in Banggood.
Link: Banggood product page
Price: -3 USD
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
Old coupons (from the oldest to the newest): BGFWF722, BGTT10, bGhOnEy10, BGdragonBoat, BGSS10%SW, BGAFF10OFF, BGCuponation10, BGDAVIS, BGHONEY2110, Parts8, BGJON8, BGRCParts8, MVC8SPRING, 8BGwbg2204
(sometimes old coupons work, so you can check them out (this site checks them on every price update))
Price history and price alert
Here is price history (for all/most countries) for HGLRC Forward F722 3-6S F7 Flight Controller.
Price records source(s): Banggood
Click on image to enlarge. 
You can set price alert (for Banggood).