Aliexpress
Click here… to search for Xiaomi EDON S108E Humidifier 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 coupon available! Pretty cool, huh?
Link: Banggood product page
Coupon (226.90 USD): 00c906
(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): BGHOMEAPP13, BGHOMEA13, 7bcdf9, BGCuponation10, BG10OFFAFF, BGwhielabel, BG10OFFAFF1, 6GSGIT
(these coupons are old, so probably won’t work)
Price history and price alert
Here is price history (for all/most countries) for Xiaomi EDON S108E Humidifier.
Price records source(s): Banggood
Click on image to enlarge. 
You can set price alert (for Banggood).