Aliexpress
Here are coupons that you can use.
Latest coupon code price check (UTC time):
Banggood
Banggood warehouse is located in China. There is one coupon right now! Check this out.
Link: Banggood product page
Coupon (35.04 USD): BG51f436
(CouponsFromChina.com tip: 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
Old coupons (from the oldest to the newest): BGQ20, band10, AFfbG10, 502C6B, BG20Q19, BGBFAFF2019, BGSAQ20, BG12Q20, BGNAQ20, 0e7f33, BGAFF10OFF, bgshOOp10, BGHALLOWEEN, BG11SHOP, BGCuponation10, BGWRIBAND10, 6GSGIT
(these codes were not working in latest coupon update, but you can check them out anyway)
Price history and price alert
Here is price history (for all/most countries) for Newwear Q20 Smart Watch.
Price records source(s): Banggood
Click on image to enlarge. 
You can set price alert (for Banggood).