Xiaomi Deerma DEM-F420 4L Air Humidifier (Banggood, Aliexpress: Model DEM-F420, Material ABS, Color White, Frequency 50Hz, Decibel ≤36 db, Voltage 220V, Timing 12 Hours, Application 31-40 ㎡, Power 20W, Capacity 4L, Humidifying Capacity 280 ml/h, Weight 1.1kg (the best price with coupon)).
Check coupons or create price alert down below. You probably want to know what is the best price?
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. ($29.18): BGDEER05
2. ($31.19): PICODICOM
coupon code has to be applied in shop’s 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, 919c60
(these codes were not working in latest coupon update, but you can check them out anyway)
Price history and price alert
Check out price history chart (for all/most countries) for Xiaomi Deerma DEM-F420 4L Air Humidifier. The lowest price was: $28.51.
Price records source(s): 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)).