Basically copy coupon, view price history or create e-mail price alert. What is the best price?
Alarm Pedometer Countdown Sport Watch 50M Waterproof
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 code price check (UTC time):
Banggood
Banggood warehouse is located in China.
Link: Banggood product page
1. ($35.05): BG1efeb0
2. ($35.43): Terence
3. ($35.43): 2203ActiesNL
4. ($35.81): BG00c906
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): men15, BGPMARS, 13f142, BGHONEY2110, BGCNNE9, BG43014, BGJWMEN15, BG33c3bd, BGd2eadf, 00c906, ADMITAD2212, 2022ACTIESNL, Tabby20
(these coupons are old, so probably won’t work)
Price history and price alert
Check out price history chart (for all/most countries) for NORTH EDGE Mars Watch.
Price records source(s): 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)).