Aliexpress
Click here… to search for Xiaomi HAGiBiS HABH1901 Wireless Display Dongle on Aliexpress
Here are coupons that you can use.
Latest coupon and price update (UTC):
Banggood
Banggood warehouse is located in China. There is one coupon available! Pretty cool, huh?
Link: Banggood product page
Coupon (36.20 USD): aff7off
(CouponsFromChina.com tip: apply code in your basket (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): BGDongle, 1225CAR, 502C6B, BGoffice1, PICODICOM, BGPAYPALSS, BGaDmITAd, BGBFAFF2019, BGCITYADS2019, 0e7f33
(these coupons are old, so probably won’t work)
Price history and price alert
Price history (for all/most countries) for Xiaomi HAGiBiS HABH1901 Wireless Display Dongle is here.
Price records source(s): Banggood
Click on image to enlarge. 
You can set price alert (for Banggood).