Just check coupons out (with price alert and history). Best price?
Battery 1×16340 Lithium Battery/CR123A/RCR123A (built-in), Brand ON THE ROAD, Charging time 40min, Material Aluminium alloy + stainless steel, Drop-proof 1m, LED 4x SST20/219CT, Waterproof IPX6, Dimensions 59x24x20mm, Charging USB-C 5V2A, Weight 80g, Illumination distance 90m, Model M4, Light intensity 2050cd
Aliexpress
There’re some similar (or not) items 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.
Link: Banggood product page
1. ($36.16): BGtorch3
2. ($38.29): BGtorch2
just apply this code 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): BG10OFFAFF1, BANGGOODSD, BGTorch4, 00c906, FIN7064
(system checks these coupons on every price check (like once per 24 hours), but you can check them out anyway)
Price history and price alert
Check out price history chart (for all/most countries) for ON THE ROAD M4 219CT Flashlight.
Price records source(s): 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)).