Aliexpress
Here are coupons that you can use.
Latest coupon code price check (UTC time):
Banggood
Banggood warehouse is located in China. Well, there is one coupon available right now.
Link: Banggood product page
Coupon (196.19 USD): BGRCEachine
(CouponsFromChina.com tip: paste coupon code in your cart and click Apply after clicking “Proceed to checkout”. Click to copy code and open shop)
Exclusive Allowance Coupons: https://bit.ly/3xWgD9k
Old coupons (from the oldest to the newest): EachineF16, BGEachine10, BG3acc39, Tabby20, BGae6c52
(you can check these old coupons out, but these probably won’t work)
Price history and price alert
Price history (for all/most countries) for Eachine F16 550mm RC Airplane PNP is here.
Price records source(s): Banggood
Click on image to enlarge. 
You can set price alert (for Banggood).