Aliexpress
Here are coupons that you can use.
Latest coupon and price update (UTC):
Banggood
Banggood warehouse is located in China. You can get coupon down below.
Link: Banggood product page
Coupon (237.59 USD): 28RC
(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): BGLAL3HD, bGhOnEy10, Eachine11, bgshOOp10, BGRC902, BgoFErTaSchInA10, BgcLuBofErtA10, BG113LAL, BGLAL3SERS, BGBFLALHD, BG10RACING, BGEachine2021
(system checks these coupons on every price check (like once per 24 hours), but you can check them out anyway)
Price history and price alert
Price history (for all/most countries) for Eachine LAL3 HD DJI 3-4S Drone PNP is here.
Price records source(s): Banggood
Click on image to enlarge. 
You can set price alert (for Banggood).