Benfica sold Orkun Kökçü to Beşiktaş for €30 million and made a good profit from the transfer.

There have also been reports claiming that Kerem Aktürkoğlu wants to leave the team. I'm not sure how accurate those reports are, but it’s said that he has been in talks with a few teams.
I have no clear idea how much he might be sold for, but he started last season really well in the league.