Basically copy coupon, view price history or create e-mail price alert. You probably want to know what is the best price?
XHP 50.2, aluminum alloy, 3x 18650 Li-ion battery, 2920 Lumens, Package Contents: 1x Flashlight, 1x Spare O-ring, 1x Metal Ring, 1x Hand Strap, 1x English User Manual
Aliexpress
I could not find it on Aliexpress. Click here to search by yourself.
Here are coupons that you can use.
Latest coupon code price check (UTC time):
Banggood
Banggood warehouse is located in China. Only one coupon available!
Link: Banggood product page
1. ($89.06): 4BLF
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 and https://couponsfromchina.com/short/5cd
Old coupons (from the oldest to the newest): 18f492, MLTVX, BGTS50, EYBG, eybg, BGTORCH, 502C6B, BGBFCR41, bGhOnEy10, bgshOOp10, BgoFErTaSchInA10, BgcLuBofErtA10, BGFLS15, BGAFF10OFF, BGCuponation10
(these codes were not working in latest coupon update, but you can check them out anyway)
Price history and price alert
Check out price history chart (for all/most countries) for MHVAST TS50 Flashlight.
Price records source(s): Gearbest, Banggood
Click on image to enlarge. 
You can set price alert (for Banggood and Aliexpress (only if product name will be the same as on Banggood and I will post it on social media though, so it’s more like Banggood price alert)).