I have checked all old coupons and price is $16.99 for MK66 1.85 inch Smart Watch (in Banggood). Basically copy coupon, view price history or create e-mail price alert. You probably want to know what is the best price?
MK66 1.85 inch HD Screen bluetooth Calling Heart Rate Blood Pressure SpO2 Monitor IP68 Waterproof Outdoor Three-proofing Smart Watch – Black
Latest coupon code price check (UTC time):
Banggood ($16.99)
Banggood warehouse is located in China. Is it cheap? Let’s see… Average price for this item is $26.69 and current one is $16.99, so it’s a good price! There is one great coupon!
Link: Banggood product page
Price without coupon: $47.99
1. ($16.99): BGc193d5
apply code in your basket (cart) 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): BG6cc351, BG734631, BGb0f219, BG760a29, BG55006a, BGa78c77, BG283218, BG454646, BGe468dc
(these codes were not working in latest coupon update, but you can check them out anyway)
Aliexpress
There’re some similar (or not) items on Aliexpress
Click here to search by yourself. Here are coupons that you can use.
Price history and price alert
Do you need price history chart (for all/most countries) for MK66 1.85 inch Smart Watch? There we go.
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)).