Aliexpress
Click here… to search for Likebook P10 eReader 10 inch 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 (327.90 USD): BGBRPL2
Coupon (327.90 USD): BGHOTSHOP15
(CouponsFromChina.com tip: paste coupon code in your cart and click Apply 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): BGb69a89, BGBuscape01, BG651551
(these codes were not working in latest coupon update, but you can check them out anyway)
Price history and price alert
Here is price history (for all/most countries) for Likebook P10 eReader 10 inch.
Price records source(s): Banggood
Click on image to enlarge. 
You can set price alert (for Banggood).