Aliexpress
Here are coupons that you can use.
Latest coupon code price check (UTC time):
Banggood
Banggood warehouse is located in China. We have found one coupon for this product!
Link: Banggood product page
Coupon (101.15 USD): BGTorch4
(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): BG18UVC, BGSUVC, BGTORCH, BGASTROLUX, BGAST25, BGAFF10OFF, BGCuponation10, 4BLF, BG10OFFAFF, BGwhielabel, BGflashlight, BG10OFFAFF1, BGdeals119, BANGGOODSD
(I don’t think these’re gonna work, but you can try ’em out anyway)
Price history and price alert
Price history (for all/most countries) for Astrolux MF01S-UVC 18x UVC+UVA Sterilizer Flashlight is here.
Price records source(s): Banggood
Click on image to enlarge. 
You can set price alert (for Banggood).