Where can I sell my Fortnite Acc?

I know that it is Bannbar, but I have invested 80 euro and my Acc is so over 300 euro worth. I would sell it for 100 like that. On which website can I do this?

You might get 30 euro-50 euro.

https://www.playerauctions.com/

I do not know if it's worth it, I've never sold one.

Not at all. You have no ownership of the account. You only have the right of use.