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 (41.96 USD): CFNKL
Coupon (41.96 USD): MHL18
Coupon (42.52 USD): YHL18
(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): CFNKM4BG
(you can check these old coupons out, but these probably won’t work)
Price history and price alert
Price history (for all/most countries) for Lumintop HL18 Headlamp is here.
Price records source(s): Banggood
Click on image to enlarge. 
You can set price alert (for Banggood).