I have checked all old coupons and price is $36.99 for Tuya Smart WiFi Weather Station (in Banggood). You can create price alert here, copy coupons and view price history. Best price?
Tuya Smart WiFi Weather Station EU Plug Indoor Outdoor Thermometer Hygrometer with Color Display Screen APP Remote Control Alarm Clock Setting Humidity Temperature Sensor Device
Latest coupon and price update (UTC):
Banggood ($36.99)
Banggood warehouse is located in China. You probably want to know if this is a good price. Well, according to CouponsFromChina database this price is the best in history (3 records). One coupon is available. Cool!
Link: Banggood product page
Price without coupon: $41.99
1. ($36.99): BGRSEPTTSWF
this code has to be applied in your cart after clicking “Proceed to checkout”. Click to copy code and open shop)
This is the best price ever noted in my database!
Exclusive Allowance Coupons: https://bit.ly/3xWgD9k and https://couponsfromchina.com/short/5cd
Old coupons (from the oldest to the newest): BG8FORMULAMX
(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
Click here to search by yourself. Here are coupons that you can use.
Price history and price alert
Price history (for all/most countries) for Tuya Smart WiFi Weather Station 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)).