Aliexpress
Here are coupons that you can use.
Other warehouses/versions
This item is available in 1 another warehouse/version!
1. Europe – Alldocube KNote X Pro N4120 8/128GB 13.3 Inch Tablet With Keyboard [EU] (-3 USD)
Latest coupon code price check (UTC time):
Banggood
Banggood warehouse is located in Hong Kong.
Link: Banggood product page
Coupon (309.99 USD): BG4f3f5d
Coupon (309.99 USD): BG72ced2
(CouponsFromChina.com tip: coupon code has to be applied in shop’s 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): BG551933, BGJULKXP, BGe323e8, BG523cf9, BGee9de5
(I don’t think these’re gonna work, but you can try ’em out anyway)
Other warehouses/versions
This item is available in 1 another warehouse/version!
1. Europe – Alldocube KNote X Pro N4120 8/128GB 13.3 Inch Tablet With Keyboard [EU] (-3 USD)
Price history and price alert
Price history (for all/most countries) for Alldocube KNote X Pro N4120 8/128GB 13.3 Inch Tablet With Keyboard is here.
Price records source(s): Banggood
Click on image to enlarge. 
You can set price alert (for Banggood).