Aliexpress
Click here… to search for Xiaomi Youpin Flower Pot Monitor on Aliexpress
Here are coupons that you can use.
Latest coupon and price update (UTC):
Banggood
Banggood warehouse is located in China.
Link: Banggood product page
Coupon (27.70 USD): e2bcea
Coupon (27.70 USD): 502C6B
Coupon (29.01 USD): vipupgrade8
Coupon (30.31 USD): aff7off
(CouponsFromChina.com tip: this code has to be applied 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): 33pot, 26POT, MIPOT10
(probably won’t work, but you can try them out)
Price history and price alert
Price history (for all/most countries) for Xiaomi Youpin Flower Pot Monitor is here.
Price records source(s): Gearbest, Banggood
Click on image to enlarge. 
You can set price alert (for Banggood).