Go down and check coupons out. Remember to check price history if it is available. Let’s see what best price is ATM.
Humidity measurement range 0%-99.9%RH, Net weight 32g, Product model XMWSDJ04MMC, Size 56.2x 56.2x 12.8mm, Product material PC/ABS, Product name Xiaomi Electronic Thermometer Hygrometer, Wireless connection Bluetooth 5.0 Bluetooth Low Energy, Temperature display resolution 0.1℃, Battery model CR2450, Humidity display resolution 0.1%RH, Temperature measurement range 0℃-60℃
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. ($17.84): BG75597c
2. ($19.10): Cuponation9
3. ($19.73): 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): BGTYSY956, BG10OFFAFF1, BANGGOODSD, 6GSGIT, BGBF20off2, BGTYPS956, 00c906, BGXPJA135, BGHealth10D, 2022ACTIESNL, BGAlerabat1, BGHB218, BGXPMA145, BGMAYB241, 2203ActiesNL, BGHECARE1, BG4ee866, BGHU2285, BGdf740b, BG9f2ee2
(these coupons are old, so probably won’t work)
Price history and price alert
Do you need price history chart (for all/most countries) for Xiaomi Mijia XMWSDJ04MMC Thermometer Hygrometer? There we go.
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)).