Use coupon and get Xiaomi Mijia Bluetooth Thermometer Hygrometer 2 for $8.21 (from Banggood). You can create price alert here, copy coupons and view price history. What is the best price?
Latest coupon code price check (UTC time):
Size 43x43x 12.5mm, CMIT ID 2019DP8115, Humidity display resolution 1 %RH, Temperature display resolution 0.1°C, Model LYWSD03MMC, Measure range 0°C-60°C, Executive standard QB/WSDJ 2401-2019, Humidity range 0%一99%RH, Wireless Connection Bluetooth 4.2 BLE, Battery CR2032, Voltage DC2.5V- -3V, Quantity 1Pcs, Material ABS+PMMA
Banggood ($8.21)
Banggood warehouse is located in China. Hmmm… There is no active coupon in Banggood at this moment. Isn’t it too expensive? Maybe there’re no more promotions for this item, because current price is higher than average (which is equal $6.74)
Link: Banggood product page
Price: $8.21
Exclusive Allowance Coupons: https://bit.ly/3xWgD9k and https://couponsfromchina.com/short/5cd
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(system checks these coupons on every price check (like once per 24 hours), 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 Xiaomi Mijia Bluetooth Thermometer Hygrometer 2 is here.
Price records source(s): Gearbest, 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)).