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 (25.99 USD): BGca3be1
Coupon (44.18 USD): BGtorch3
Coupon (46.78 USD): BGtorch2
(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): BGIU, FLSTNE, LTNH, ltnh, BGTORCH, 502C6B, BGBFCR41, BGAFF10OFF, BGCuponation10, 4BLF, BGHONEY2110, BG10OFFAFF, BG10OFFAFF1, BANGGOODSD, BGTorch4, 00c906
(probably won’t work, but you can try them out)
Price history and price alert
Check out price history chart (for all/most countries) for Klarus ST30-U Flashlight.
Price records source(s): Banggood
Click on image to enlarge. 
You can set price alert (for Banggood).