Aliexpress
Here are coupons that you can use.
Latest price update (UTC time):
Banggood
Banggood warehouse is located in China.
Link: Banggood product page
Coupon (399.96 USD): Drones6
Coupon (399.96 USD): CouponsDE
Coupon (399.96 USD): 00c906
(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): BGIFXL5, bGhOnEy10, BGdragonBoat, BGTITANXL5, BGSS10%SW, BGXL5T, bgshOOp10, BGRC902, BgoFErTaSchInA10, BGXL56S, BgcLuBofErtA10, BGAFF10OFF, BG10RACING, BGMATT7, BGDAVIS, BANGGOODSD
(these coupons are old, so probably won’t work)
Price history and price alert
Here is price history (for all/most countries) for iFlight TITAN XL5 250mm 6S Drone.
Price records source(s): Banggood
Click on image to enlarge. 
You can set price alert (for Banggood).