I have just checked coupons. The lowest price I could get is 49.99 USD for 3 50m (in Banggood). Price history, coupons and price alert are available on this page. What is the best price?
Latest coupon and price update (UTC):
Banggood (49.99 USD)
Banggood warehouse is located in China. There are no active coupons for this product, but the price is pretty low isn’t it? Is it expensive? From what I can see this price is higher than average price (22.79 USD).
Link: Banggood product page
Price: 49.99 USD
Exclusive Allowance Coupons: https://bit.ly/3xWgD9k
Old coupons (from the oldest to the newest): BGRD11MARS3
(these coupons are old, so probably won’t work)
Aliexpress
Click here… to search for NORTH EDGE Mars 3 50m Smart Watch on Aliexpress
Here are coupons that you can use.
Price history and price alert
Check out price history chart (for all/most countries) for NORTH EDGE Mars 3 50m Smart Watch.
Price records source(s): Banggood
Click on image to enlarge. 
You can set price alert (for Banggood).