Aliexpress
Here are coupons that you can use.
Latest price update (UTC time):
Banggood
Banggood warehouse is located in Hong Kong.
Link: Banggood product page
Coupon (489.99 USD): BGBF20PU
Coupon (489.99 USD): BGCB20P
(CouponsFromChina.com tip: apply code in your basket (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): BGEUTO20, BGBWEU412, BGTBEU20, BGEUTOB20, 6GSGIT, BGPREU20, BGTEU20P, BGRBF28, BGBFIT20P
(sometimes old coupons work, so you can check them out (this site checks them on every price update))
Price history and price alert
Check out price history chart (for all/most countries) for Teclast T.BOLT 20 Pro Laptop 15.6 inch i5-8259U 8/256GB.
Price records source(s): Banggood
Click on image to enlarge. 
You can set price alert (for Banggood).