Hi!
May I know when is the good time to buy and sell players?

I think selling players near the end of the season will better and buying new players will be at the start or even mid-season since they will get deduct 20% if we got a promotion.

May I right to say that? Or should i get new fast players near the end season so i can purchase them at a cheaper rate. Currently i am at level 1 and will be promoting after this season.

Appreciate anyway can guide me? Thanks!