Aliexpress
Click here… to search for ASUS Y406UA8250 i5-8250U 8/256GB Laptop 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 (722.60 USD): aff7off
Coupon (756.99 USD): Wholesale20
(CouponsFromChina.com tip: just apply this code in your cart after clicking “Proceed to checkout”. Click to copy code and open shop)
Old coupons (from the oldest to the newest): 401BG1445406, BGASUS2, BGAS406
(I don’t think these’re gonna work, but you can try ’em out anyway)
Price history and price alert
Here is price history (for all/most countries) for ASUS Y406UA8250 i5-8250U 8/256GB Laptop.
Price records source(s): Banggood
Click on image to enlarge. 
You can set price alert (for Banggood).