Aliexpress
Here are coupons that you can use.
Latest price update (UTC time):
Banggood
Banggood warehouse is located in China. So I have checked for active coupons (all category coupons and old ones), but there was no working coupon in Banggood.
Link: Banggood product page
Price: -3 USD
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
Old coupons (from the oldest to the newest): 5719ed, 3ef692, 20thor4, 502C6B, e2bcea, zeblaze10, BGThor4, BGIL4G, BG8THOR4, BGTROP4, BGWKTHOR4, BG3CSUM, PICODICOM, BGZBTHOR4, bgwp, BGTHOR4109, 8fbade, BGNAZT4, BGWKZBT4, BGBFZBT4, BGZeblaze10
(there’s a little possibility that old coupon will work)
Price history and price alert
Price history (for all/most countries) for Zeblaze THOR 4 Smartwatch is here.
Price records source(s): Gearbest, Banggood
Click on image to enlarge. 
You can set price alert (for Banggood).