Aliexpress
Click here… to search for A4 LED Ultra-Thin Dimmable Brightness Light Board [EU] on Aliexpress
Here are coupons that you can use.
Latest coupon code price check (UTC time):
Banggood
Banggood warehouse is located in Europe 
. I don’t know if this is a good price – number of records in my database is too low!
Link: Banggood product page
Coupon (21.11 USD): BG1fa1b2
Coupon (22.55 USD): BG00c906
(CouponsFromChina.com tip: apply it in your 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): 2022ACTIESNL, BG1efeb0, 8Couponsde, MVC8SPRING, 8BGwbg2204, 2203ActiesNL, tRaDetRaCKeR, 8wEbgaInS5, pROMo8cuPoN
(probably won’t work, but you can try them out)
Price history and price alert
It doesn’t make sense to generate price history chart, because there is one price record which is: 9.99 USD.
You can set price alert (for Banggood).