Go down and check coupons out. Remember to check price history if it is available. 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):
IP rating: 5ATM, Bluetooth Version: Bluetooth 5.0, Screen size: 1.39 inch, ROM: 512MB, Screen resolution: 320x 320, Waterproof / Water-Resistant: Yes, Screen: IPS, RAM: 128KB, Operating mode: Touch Screen, Model Number: Stratos 3
Banggood
Banggood warehouse is located in Hong Kong. There are no coupons for this product in Banggood.
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): BGAS3199, bgwp, BGAS3198, BGNAAFS3, BGAMZ200, BGAM3EN, amazfit100, BGABS3, BGAS3192, 7d18f7, BGA3CU, BGA3174, BGAM35, BGAS179, BGAS174, AS136, BGDQAS3, BGILAF3, BGAS139, BGPowerstation, BGAS134, BGZBAS3, BG11AS3, Email5, BGAFAMS, BGAS3U, BGBFSTR3, BGAS3BF, BGBRAS3, BGFabioamaz, 6GSGIT, BG3a5e6d
(these codes were not working in latest coupon update, but you can check them out anyway)
Price history and price alert
Here is price history (for all/most countries) for Amazfit Stratos 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)).