Aliexpress
Click here… to search for Xiaomi Solove 230ml Air Humidifier Night Light White on Aliexpress
Here are coupons that you can use.
Latest price update (UTC time):
Banggood
Banggood warehouse is located in China.
Link: Banggood product page
Coupon (17.30 USD): BGHONEY2110
Coupon (17.30 USD): BG10OFFAFF
Coupon (17.30 USD): BGwhielabel
Coupon (18.22 USD): 13f142
(CouponsFromChina.com tip: apply it 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, TTxBG10, BGSolove12, aff7off, AFfbG10, affbg10, BGVDay10%off, BGHOMEG12, BGAFF10OFF, BGTT10, bGhOnEy10, BGdragonBoat, BGSS10%SW, bgshOOp10, BGHome15%, BGHOMEA15%, BgcLuBofErtA10, BGCuponation10
(these coupons are old, so probably won’t work)
Price history and price alert
Check out price history chart (for all/most countries) for Xiaomi Solove 230ml Air Humidifier Night Light White.
Price records source(s): Gearbest, Banggood
Click on image to enlarge. 
You can set price alert (for Banggood).