Go down and check coupons out. Remember to check price history if it is available. What is best price?
Battery Capacity: 130mAh, Size: 1.14inch, more accurately monitor), Charging Time: About 2 hours, Waterproof IP68, Resolution: 135*240pixels, (updated Sensor, Heart Rate Sensor: PD70-01C-TR7, Charging Type: USB Direct Charging, Main Chip NRF52832, G-sensor: KX023-1025, Type: IPS, Standby Time: About15 days, Using time: About 5 days
Aliexpress
There’re some similar (or not) items on Aliexpress
Click here to search by yourself. Here are coupons that you can use.
Latest price update (UTC time):
Banggood
Banggood warehouse is located in China. I’m afraid that there’s no working coupon in Banggood.
Link: Banggood product page
Price: $-3
It looks like this item is out of stock in Banggood. If you found it then please send me the link. I will replace it.
Click here to search on Banggood!
Exclusive Allowance Coupons: https://bit.ly/3xWgD9k and https://couponsfromchina.com/short/5cd
Old coupons (from the oldest to the newest): band10, newwear10, AFfbG10, BGBFAFF2019, BGBFQ18, BGVDay10%off, FBCOUPON1, BGCuponation10, BGWRIBAND10
(these codes were not working in latest coupon update, but you can check them out anyway)
Price history and price alert
Price history (for all/most countries) for Newwear Q18 Smart Watch is here.
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)).