Basically copy coupon, view price history or create e-mail price alert. Best price?
Brand NITECORE, Green Flashing: 300h, Red/Blue Police Warning Flashing: 72h, White Flashing: 300h, Runtime Blue Flashing: 330h, Red Flashing: 360h, Weight 34g / 1.2oz, Model TSL10i, Size 32×46.2mm / 1.26×1.82inch
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. There is one coupon right now! Check this out.
Link: Banggood product page
1. ($26.32): BG10OFFAFF1
apply it 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): BGFLS15, BGAFF10OFF, BGCuponation10, 4BLF, BGHONEY2110, BG10OFFAFF, BGwhielabel
(these coupons are old, so probably won’t work)
Price history and price alert
Do you need price history chart (for all/most countries) for Nitecore TSL10i Flashlight Taillight? There we go.
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)).