Aliexpress
Click here… to search for Xiaomi Mijia Luke CatY Video Doorbell on Aliexpress
Here are coupons that you can use.
Latest coupon and price update (UTC):
Banggood
Banggood warehouse is located in China.
Link: Banggood product page
Coupon (159.99 USD): BGLKBELL
Coupon (178.49 USD): BGBK15
(CouponsFromChina.com tip: 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
Old coupons (from the oldest to the newest): BGXMCatY, Wholesale20, bgssaff9, wholesale20, BGaDmITAd, BGLUKEC10, BGAQ20, BGBAK15
(these coupons are old, so probably won’t work)
Price history and price alert
Here is price history (for all/most countries) for Xiaomi Mijia Luke CatY Video Doorbell.
Price records source(s): Banggood
Click on image to enlarge. 
You can set price alert (for Banggood).