Just check coupons out (with price alert and history). Let’s see what best price is ATM.
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):
LED indicator: Blue, Connection: Wi-Fi 2.4GHz, IR Remote Control Distance: ≤10m, Infrared Frequency: 38KHz, Temperature Accuracy: ±1℃, Humidity Accuracy: ±5%RH, Temperature Measure Range: 0℃~60℃, Input: DC 5V/1A(Micro USB NO Adapter), App: Tuya Smart or Smart Life, Size: 65mmx 65mmx 17mm, Humidity Measure Range: 0%RH~99%RH
Banggood
Banggood warehouse is located in Europe 
. This is new product in my database, so I don’t know if this price is good.
Link: Banggood product page
1. ($21.83): Cuponation9
2. ($22.07): BG8ReviTrage
just apply this code in your cart after clicking “Proceed to checkout”. Click to copy code and open shop.
Exclusive Allowance Coupons: https://bit.ly/3xWgD9k and https://couponsfromchina.com/short/5cd
Old coupons (from the oldest to the newest): BGSmart6, pROMo8cuPoN, BGJUNEGSG9, 9OFFSUMMER
(sometimes old coupons work, so you can check them out (this site checks them on every price update))
Price history and price alert
It’s a new item in our database, so I can’t create price history chart. We have saved this price in database: $20.39.
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)).