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 (226.22 USD): BGTT10
Coupon (226.22 USD): bGhOnEy10
Coupon (226.22 USD): BGdragonBoat
(CouponsFromChina.com tip: just apply this code in your cart 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): BGGTR569, BGCITYADS2019, AFfbG10, BGWKR569, BGVDay10%off, BGSS10%SW, bgshOOp10
(probably won’t work, but you can try them out)
Price history and price alert
Check out price history chart (for all/most countries) for Diatone 2019 GTR569 5 Inch 6S PNP Drone.
Price records source(s): Banggood
Click on image to enlarge. 
You can set price alert (for Banggood).