Basically copy coupon, view price history or create e-mail price alert. You probably want to know what is the best price?
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 and price update (UTC):
Charging Time: About 2 hours, Heart Rate Monitor Support, Using time: About 7-10 days, Waterproof IP68, Multi-sport Mode Support / Build-in 20 sports, Blood Oxygen Monitor Support, Model MAGIC 3, Charging Method: Magnetic, Type: TFT, Battery Capacity: 220mAh, CPU nRF52840, Brand KOSPET, Standby Time: About 35 days, Pixel: 280*320, bluetooth Version BT 5.0, Size: 1.71 inch
Banggood
Banggood warehouse is located in China.
Link: Banggood product page
1. ($46.91): BGc70579
2. ($46.91): BGbf11dd
put item in your cart and apply coupon code there 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): BGMAGIC3, band10, BGEEUKOSPET, BGKPMG3, BG833a30, BGKOPMG3, BGaa8131, BG770359, BG20177f, BG51f436, BG390b08, BG305434, BGde249f, BGbda786, BG343102, BG83c8e9, BGad8fc0, BGfd149b
(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 KOSPET Magic 3 Smart Watch.
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)).