Aliexpress
Here are coupons that you can use.
Latest coupon and price update (UTC):
Banggood
Banggood warehouse is located in China. There is one coupon right now! Check this out.
Link: Banggood product page
Coupon (31.16 USD): BGtorch2
(CouponsFromChina.com tip: apply code in your basket (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): BGMFET, linepayflt, EYBG, 8a955d, BGBFCR41, BGBFCR40, AXMAS, BGTORCH, BGASTROLUX, BGAST25, BGAFF10OFF, BGCuponation10, 4BLF, BGHONEY2110, BG10OFFAFF, BGwhielabel, BG10OFFAFF1, BGCL27, BANGGOODSD, BGTorch4, 00c906, BGtorch3, BGAlerabat15, BGtorch7
(probably won’t work, but you can try them out)
Price history and price alert
Price history (for all/most countries) for Extension Flashlight Tube for ASTROLUX MF01 MF02 MF02S MF04 MF04S is here.
Price records source(s): Banggood
Click on image to enlarge. 
You can set price alert (for Banggood).