Aliexpress
Here are coupons that you can use.
Latest coupon code price check (UTC time):
Banggood
Banggood warehouse is located in China. One coupon is available. Cool!
Link: Banggood product page
Coupon (110.39 USD): BGMatt2022
(CouponsFromChina.com tip: coupon code has to be applied in shop’s cart after clicking “Proceed to checkout”. Click to copy code and open shop)
Exclusive Allowance Coupons: https://bit.ly/3xWgD9k
There were country-specific coupon codes published on Couponsfromchina social channels and price alerts. Coupon price may vary by country, because there’re different VAT rates, shipping cost etc. There is a chance that some latest coupons are still working:
Old coupons (from the oldest to the newest): BGc79fff, Drones6, BANGGOODSD, CouponsDE, 00c906, BGJON8, Tabby20, 8Couponsde, MVC8SPRING, 8BGwbg2204, tRaDetRaCKeR, 8wEbgaInS5, BG8RCToy, hoNEYbGdeAlS, BGJUNEGSG9, BGRCT10, BG8ReviTrage, Cuponation9, COUPONSDE1wk, BgGoodie9, BGToys8, BGSaleFeb8, BGSaleAD
(there’s a little possibility that old coupon will work)
Price history and price alert
Here is price history (for all/most countries) for ATOMRC Fixed Wing Dolphin RC Airplane KIT LITE.
Price records source(s): Banggood
Click on image to enlarge. 
You can set price alert (for Banggood).