Aliexpress
Here are coupons that you can use.
Latest coupon and price update (UTC):
Banggood
Banggood warehouse is located in China. Only one coupon available!
Link: Banggood product page
Coupon (315.81 USD): BG10OFFAFF1
(CouponsFromChina.com tip: you should apply the coupon 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): BGLMTB, BGFLS15, BGwhielabel, BGflashlight
(there’s a little possibility that old coupon will work)
Price history and price alert
Price history (for all/most countries) for LUMINTOP FW3A Mokume/Damast Flashlight is here.
Price records source(s): Banggood
Click on image to enlarge. 
You can set price alert (for Banggood).