Basically copy coupon, view price history or create e-mail price alert. You probably want to know what is the best price?
Endurance 3h, Battery Capacity 70mA, Size 50x 0.9x 0.9cm, Color Blue, Weight 30g
Aliexpress
I could not find it on Aliexpress. Click here to search by yourself.
Here are coupons that you can use.
Latest price update (UTC time):
Banggood
Banggood warehouse is located in China. As you can see I didn’t find any active coupon for this product right now…
Link: Banggood product page
Price: $-3
It looks like this item is out of stock in Banggood. If you found it then please send me the link. I will replace it.
Click here to search on Banggood!
Exclusive Allowance Coupons: https://bit.ly/3xWgD9k and https://couponsfromchina.com/short/5cd
Old coupons (from the oldest to the newest): BGMLQW, BGCITYADS2019, BGQJPKP, BGWKJP2, AFfbG10, BGLDCT7, BGPJPP, BGFFDJP, BGHFGJP, BGHOMEG12, 13f142, BGAFF10OFF, bGhOnEy10, BGHDDXQJP, BGJJCWJP, bgshOOp10, BGHome15%, BgcLuBofErtA10, BGCuponation10, BGHONEY2110
(probably won’t work, but you can try them out)
Price history and price alert
Here is price history (for all/most countries) for XL81-5001 LED Pet Collar.
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)).