According to my DB the lowest price is $107.63 for Xiaomi Mijia Desktop Air Purifier (in Banggood). Price history, coupons and price alert are available on this page. You probably want to know what is the best price?
Xiaomi Mijia Desktop Air Purifier Original Personal Air Cleaner Antibacterial Purifiers Filtration With Mi Home APP Office Home
Latest coupon code price check (UTC time):
Banggood ($107.63)
Banggood warehouse is located in China. Isn’t it too expensive? The average price for this item is $109.20, so I think it’s a good price! You can get coupon down below.
Link: Banggood product page
Price without coupon: $116.99
1. ($107.63): BGALL8
put item in your cart and apply coupon code there 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): BGBFDAY8, BGNEWYEAR8, BGSPRING8OFF, BGHONEYSP, BGESJY8
(probably won’t work, but you can try them out)
Aliexpress
There’re some similar (or not) items on Aliexpress
Click here to search by yourself. Here are coupons that you can use.
Price history and price alert
Price history (for all/most countries) for Xiaomi Mijia Desktop Air Purifier is here.
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)).