Aliexpress
Here are coupons that you can use.
Latest coupon and price update (UTC):
Banggood
Banggood warehouse is located in Hong Kong.
Link: Banggood product page
Coupon (969.99 USD): BGXMPK7
Coupon (969.99 USD): BGXMPK8
Coupon (1179.99 USD): Wholesale20
(CouponsFromChina.com tip: you should apply the coupon in your 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): 88BGMI, 93BGHOT, JQMI14, EBGS5, PCNETWORK, 10BGMP, 10BGMPD, 10BGMPSS, 1B1G1LAP1, 1B1G18385, 1B2G0X5M885, 1B2G85X, 19BG855X, 19855XBG, 25855XBG, TECH8%, 312855XBG, 326710BG, 326855XBG, 402855XBG, bg855xlow, BGXM8521, aff7off, BGXM8572, BGXM9402, BGXM0718, BGXM78550U, affiliate6, BGXM8550U1, bg85516, BGON855, BGXMPI7
(these coupons are old, so probably won’t work)
Price history and price alert
Here is price history (for all/most countries) for Xiaomi Mi Notebook Pro 16/256GB i7-8550U MX150.
Price records source(s): Gearbest, Banggood
Click on image to enlarge. 
You can set price alert (for Banggood).