Aliexpress
Click here… to search for Xiaomi Youpin Fanmi Wireless Thermometer on Aliexpress
Here are coupons that you can use.
Latest coupon code price check (UTC time):
Banggood
Banggood warehouse is located in China. There is one great coupon!
Link: Banggood product page
Coupon (51.74 USD): BG10OFFAFF1
(CouponsFromChina.com tip: you should apply the coupon in your cart after clicking “Proceed to checkout”. Click to copy code and open shop)
Exclusive Allowance Coupons: https://bit.ly/3xWgD9k
Old coupons (from the oldest to the newest): vipupgrade8, FMTHM, ML15%Pro, BGTS0, BGPSTM0, BGFMTM, BGHC715, BGFMT3, BGTHERPL, 502C6B, BGNOV9, BGPL11FAN, BGCPFEVER, BGBFHC30, BGB59253, BGbeauty001, bGhOnEy10, bgshOOp10, BGHB20, BgoFErTaSchInA10, BGSD12356, BgcLuBofErtA10, 13f142, BG10OFFAFF, BGwhielabel, BGTURISL, BGFANMIT
(sometimes old coupons work, so you can check them out (this site checks them on every price update))
Price history and price alert
Check out price history chart (for all/most countries) for Xiaomi Youpin Fanmi Wireless Thermometer.
Price records source(s): Gearbest, Banggood
Click on image to enlarge. 
You can set price alert (for Banggood).