MoesHouse Tuya ZB Smart Window Door Sensor (Banggood, Aliexpress: Wireless Technology: ZB 3.0, Size Small Body: 25*10*9mm, Transmission Frequency: 2.4GHz, Size Main Body: 40*25*12mm, Working Voltage: 2.4V-3.3V(CR2032 battery), Transmission Range: Indoor: 10~30m/Outdoor: 30~50m, Working Temperature: ‒20°C ~+60°C; 0%~95%RH (the best price with coupon)).
Go down and check coupons out. Remember to check price history if it is available. Do you want to know what the best price is?
Aliexpress
There’re some similar (or not) items on Aliexpress
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 no active coupon in my database right now (for 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): Cuponation9, BG864dcc
(I don’t think these’re gonna work, but you can try ’em out anyway)
Price history and price alert
Check out price history chart (for all/most countries) for MoesHouse Tuya ZB Smart Window Door Sensor. The lowest price was: $6.99.
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)).