$11.39 – MoesHouse Smart WiFi Temperature Humidity Sensor Wiress APP Remote Monitoring Control Indoor Hygrometer Thermometer Controller Battery Powered Work with Alexa Google.
ATM you can buy MoesHouse Smart WiFi Temperature Humidity Sensor for $11.39 (in Banggood). Price history, coupons and price alert are available on this page. Best price?
Latest coupon and price update (UTC):
Banggood ($11.39)
Banggood warehouse is located in China. So I have checked for active coupons (all category coupons and old ones), but there was no working coupon in Banggood. What about the price? My database says that it’s pretty good price, coz average is $11.79.
Link: Banggood product page
Price: $11.39
Additional Banggood coupons: first page and second page
Old coupons (from the oldest to the newest): BGeb2742
(these codes were not working in latest coupon update, but you can check them out anyway)
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.
Price history and price alert
Check out price history chart (for all/most countries) for MoesHouse Smart WiFi Temperature Humidity Sensor. The lowest price was: $10.99.
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)).