Aliexpress
Here are coupons that you can use.
Latest coupon code price check (UTC time):
Banggood
Banggood warehouse is located in China.
Link: Banggood product page
Coupon (250.55 USD): BG28RC
Coupon (327.11 USD): Drones6
(CouponsFromChina.com tip: this code has to be applied 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): BG10RACING, 7bcdf9, BGMATT7, BGREKON5E, BGREKON15, BGDAVIS, BGR5GM, BG9dc12b
(these codes were not working in latest coupon update, but you can check them out anyway)
Price history and price alert
Here is price history (for all/most countries) for Rekon 5 5Inch 4S Drone HD Nebula Pro.
Price records source(s): Banggood
Click on image to enlarge. 
You can set price alert (for Banggood).