Aliexpress
Click here… to search for ASUS Pegasus 3S 3/64GB Black 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 (197.79 USD): Email5
Coupon (197.79 USD): bgshOOp10
(CouponsFromChina.com tip: paste coupon code in your cart and click Apply after clicking “Proceed to checkout”. Click to copy code and open shop)
Old coupons (from the oldest to the newest): affiliate6, aff7off, bgssaff9, od7off, BGaDmITAd, 7bcdf9, BGBFAFF2019, BGCITYADS2019, BGMPB2020
(you can check these old coupons out, but these probably won’t work)
Price history and price alert
Price history (for all/most countries) for ASUS Pegasus 3S 3/64GB Black is here.
Price records source(s): Gearbest, Banggood
Click on image to enlarge. 
You can set price alert (for Banggood).