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 (157.34 USD): BGac7701
Coupon (220.28 USD): BG30BETAFPV
(CouponsFromChina.com tip: apply it 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): BG85XHD, bGhOnEy10, BgcLuBofErtA10, BGBeta85X, BG11WHOOP, BGBT15VIP, BG85X20, BG10RACING, BGCuponation10, BGBETA10, BGDAVIS, BGe68b81
(these codes were not working in latest coupon update, but you can check them out anyway)
Price history and price alert
Check out price history chart (for all/most countries) for BetaFPV Beta85X Whoop HD Digital 3S Drone.
Price records source(s): Banggood
Click on image to enlarge. 
You can set price alert (for Banggood).