Operating Mode Full-Touch, Model GTS3, Compatible OS Android 4.4 or above; iOS 9.0 or above, Bluetooth Version BT 5.0, APP Name JYOUPRO, Brand SENBONO.
Just check coupons out (with price alert and history). What is best price?
Aliexpress
There’re some similar (or not) items on Aliexpress
You can use link bot to get even lower price:
Click here to search by yourself. Here are coupons that you can use.
Latest coupon and price update (UTC):
Banggood
Banggood warehouse is located in China. There is one great coupon!
Link: Banggood product page
1. ($15.99): BG2d1c4e
put item in your cart and apply coupon code there after clicking “Proceed to checkout”. Click to copy code and open shop.
Additional Banggood coupons: first page and second page
Old coupons (from the oldest to the newest): BG063f83, BG040c73, BG69702b, BG33a157, BGb3f922, BG6ec858, BGefa0f4, BGa8113f, BG7a9b6d, BGc70579, BGHOBBY02, BGbf11dd, BGRSUNGTS3, BGJP61704, BGHU2246, BGa32b12, BG261b43, BG133c02, BG452598, BG43539a, BGa38086, BGfe1ae7, BG354d70, BGb1256c, BG217661
(there’s a little possibility that old coupon will work)
Price history and price alert
Do you need price history chart (for all/most countries) for SENBONO GTS3 Smart Watch? There we go. The lowest price was: $15.99.
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)).