Aliexpress
Here are coupons that you can use.
Latest coupon and price update (UTC):
Banggood
Banggood warehouse is located in China.
Link: Banggood product page
Coupon (384.79 USD): BG05662b
Coupon (432.89 USD): BG8f150c
Coupon (442.51 USD): BGJON8
Coupon (442.51 USD): BGMatt2022
(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): BG7aacc6, CouponsdeFPV, MVC8SPRING, 8BGwbg2204, tRaDetRaCKeR, 8wEbgaInS5, pROMo8cuPoN, BG8RCToy, hoNEYbGdeAlS, BGToys1, BGRCT10, BGJUNEGSG9, DealBGimpact, Cuponation9, 9OFFSUMMER, BgGoodie9
(probably won’t work, but you can try them out)
Price history and price alert
Price history (for all/most countries) for Diatone Roma F4 4 Inch HD 4S/6S Drone is here.
Price records source(s): Banggood
Click on image to enlarge. 
You can set price alert (for Banggood).