Go down and check coupons out. Remember to check price history if it is available. Best price?
Communication method WIFI 2.4G, Weight 70g, Power supply mode DC 4.5V (3 AAA batteries), Working temperature -10~+55℃ 0~100%RH, Size 65x60x26mm/2.51×2.36×1.02in, Material ABS/PC
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 code price check (UTC time):
Banggood
Banggood warehouse is located in China.
Link: Banggood product page
1. ($22.47): BGAlerabat1
2. ($24.85): BG00c906
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): BGTY071, BG10OFFAFF1, BGTYOC071, BANGGOODSD, 6GSGIT, BGPA071, 00c906
(these coupons are old, so probably won’t work)
Price history and price alert
Price history (for all/most countries) for Tuya Smart WiFi Temperature Humidity Sensor 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)).