Just check coupons out (with price alert and history). What is the best price?
Measuring range: 32 – 42 Deg.C, Error range: 0.1 Deg.C (35 – 39 Deg.C), 0.2 Deg.C (less than 35 Deg.C, or more than 39 Deg.C), Operation environment: 5 – 40 Deg.C, less or equal to 85 percent RH, Built-in 1x button battery
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 and price update (UTC):
Banggood
Banggood warehouse is located in China.
Link: Banggood product page
1. ($6.43): MVC8SPRING
2. ($6.57): BG00c906
3. ($6.57): BGHB218
apply it 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): 502C6B, code1573, CODE1573, BGbabyTM, BGHOMEG12, AFfbG10, BGbbtt28, BGmat58, FBCOUPON1, BGAFF10OFF, bGhOnEy10, BGdragonBoat, bgshOOp10, BgoFErTaSchInA10, BGHOMEA15%, BgcLuBofErtA10, BGCuponation10, 13f142, BGHONEY2110, BGZX926, BANGGOODSD, 00c906, BGHealth10D, 2022ACTIESNL
(these codes were not working in latest coupon update, but you can check them out anyway)
Price history and price alert
Here is price history (for all/most countries) for Xiaomi MiaoMiaoCe Digital Baby Thermometer.
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)).