Can I charge 250 euro for the laptop?

https://www.ebay-kleinanzeigen.de/s-anzeige/toshiba-europe-toshiba-satellite-l50d-b-131-amd-a8-6410/1440623708-278-4905

Rather 150-200 euro. And that would be good.

No… The thing is 5 years old and cost 450 euro at the time

150 maximum. And you can take "very fast laptop" out of the text right away, because that is absolutely not true

And once there's something from Windows 10, below 8.1

I can get a new laptop for a little more money, which is even faster

Max 150 euro

You wouldn't get more on ebay