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 (319.94 USD): BGBFCR28
Coupon (335.49 USD): Wholesale20
(CouponsFromChina.com tip: put item in your cart and apply coupon code there 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): 424BG909, 5BG909, BGX924, aff7off, BGJL3D04, BGTBX9, BGTBX6588, BGTBX9032, affiliate6, BGTB8909, BGTB89091, BGTBA7, BGTBA8, BGTBA9, BGTBS1, BGTBS2, BGTBV11P
(these codes were not working in latest coupon update, but you can check them out anyway)
Price history and price alert
Check out price history chart (for all/most countries) for T-Bao Tbook X9 8/128GB i3-5005U Laptop.
Price records source(s): Banggood
Click on image to enlarge. 
You can set price alert (for Banggood).