Best time to buy/sell players

[cookizzz]

So while i am at lower leagues sell players at the end of the season and when i get to like lvl 10, then sell them in the beginning basically?

If you can sell unused players now, selling them before season end. You will get higher return. But there will be less available players when next season begins.

However, as you promotes to higher levels, you will find more & more difficult to sell players near season end. Moreover, the reduce of selling price after season begins will be less important to your team.