Aliexpress
Click here… to search for Xiaomi Mijia Aqara Smart IP Camera on Aliexpress
Here are coupons that you can use.
Latest price update (UTC time):
Banggood
Banggood warehouse is located in China.
Link: Banggood product page
Coupon (35.59 USD): vipupgrade8
Coupon (37.59 USD): 5AQCAM
Coupon (37.99 USD): smartbuy
Coupon (37.99 USD): 3AQCAM
(CouponsFromChina.com tip: apply it in your cart after clicking “Proceed to checkout”. Click to copy code and open shop)
Price history and price alert
Price history (for all/most countries) for Xiaomi Mijia Aqara Smart IP Camera is here.
Price records source(s): Gearbest, Banggood
Click on image to enlarge. 
You can set price alert (for Banggood).