Aliexpress
Here are coupons that you can use.
Latest price update (UTC time):
Banggood
Banggood warehouse is located in China.
Link: Banggood product page
Coupon (56.22 USD): BGc70579
Coupon (56.22 USD): BGbf11dd
(CouponsFromChina.com tip: apply it in your cart after clicking “Proceed to checkout”. Click to copy code and open shop)
Exclusive Allowance Coupons: https://bit.ly/3xWgD9k
Old coupons (from the oldest to the newest): BGDT03, 6GSGIT, BG011f9a, BG51f436, BG94322e, BG3122d7, BGDT3FANS, BG2202FANS13, BGaa54dd
(there’s a little possibility that old coupon will work)
Price history and price alert
Check out price history chart (for all/most countries) for DT.NO1 DT3 Smart Watch.
Price records source(s): Banggood
Click on image to enlarge. 
You can set price alert (for Banggood).