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 (392.99 USD): Email5
Coupon (392.99 USD): BG6c5fab
(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): bgshOOp10
(there’s a little possibility that old coupon will work)
Price history and price alert
Do you need price history chart (for all/most countries) for Alldocube KNote 8 Lite 6Y30 8/256GB Tablet? There we go.
Price records source(s): Banggood
Click on image to enlarge. 
You can set price alert (for Banggood).