Aliexpress
Click here… to search for I4 Air 2/16GB Smartwatch on Aliexpress
Here are coupons that you can use.
Latest coupon and price update (UTC):
Banggood
Banggood warehouse is located in China.
Link: Banggood product page
Coupon (98.99 USD): AFfbG10
Coupon (102.29 USD): aff7off
(CouponsFromChina.com tip: coupon code has to be applied in shop’s cart after clicking “Proceed to checkout”. Click to copy code and open shop)
Old coupons (from the oldest to the newest): TTxBG10, BGI459, BGss11, BGPAYPALSS
(there’s a little possibility that old coupon will work)
Price history and price alert
Price history (for all/most countries) for I4 Air 2/16GB Smartwatch is here.
Price records source(s): Gearbest, Banggood
Click on image to enlarge. 
You can set price alert (for Banggood).