Buying a player that cost a lot of tokens and/or virtual money, especially from the scout's list and recommendations' list at such a time in the season is not good as he will lose one star next season (which is only in about 2 days here), unless your team failed to promote to the next level. You must buy such players early in the season, or at most at the end of week 2, but there can be some exceptions if the right player appears in week 3. Suppose that you want to sell him at the start of next season, it will be a loss as players have a drop in market value at the start of each season.
You can still sell some of those fast trainers before the end of this season in order to provide money for transfers at the start of next season.