Price history, coupons and price alert are available on this page. You probably want to know what is the best price?
Driver 12 groups max current output 8000mA / Temperature protection management inside, Length 126.5 mm, Material Aluminum Alloy, Required battery type 21700 lithium battery(unprotected and length not more than 71mm), Required battery quantity 1pcs, Flux Max 2000LM, LED Nichia 219B 4500K / 519A 4500K, Lens type Ar-coated glass and 60 degree bead TIR lens, Mode memory Yes, Low voltage warning Yes, Tailstand Yes, CRI Ra>90 /R9>90 /R12>70, Reverse polarity protection Yes, Weight 106g, Battery included No, Diameter(Head/Body) 32.1 / 27.2 mm
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. ($35.19): BGOutlight10
coupon code has to be applied in shop’s 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): BGAlerabat15, F36855, BGtorch7, BGtorch2, FIN6244, BGAlerabatI, BG5f6ff9
(you can check these old coupons out, but these probably won’t work)
Price history and price alert
Check out price history chart (for all/most countries) for Convoy S21D 519A 4500K 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)).