Aliexpress
Here are coupons that you can use.
Latest coupon and price update (UTC):
Banggood
Banggood warehouse is located in China. We have found one coupon for this product!
Link: Banggood product page
Coupon (514.79 USD): BG10OFFAFF1
(CouponsFromChina.com tip: paste coupon code in your cart and click Apply 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): 7bcdf9, BGCuponation10, BG10OFFAFF, BGwhielabel
(sometimes old coupons work, so you can check them out (this site checks them on every price update))
Price history and price alert
Here is price history (for all/most countries) for Xiaomi Mijia MJXFJ-150-A1 Wall-mounted Air Purifier.
Price records source(s): Banggood
Click on image to enlarge.
You can set price alert (for Banggood).