I won so far about 10M with 8m from cup and league, 1.5 from sales, sold 10 players, received 1 good U21 and a médium one. The rest from tickets and so on.
You can buy cheapest players, the only problem is that they are not fast trainer, i just bought 1 for 1,7M, 18 years old, 2,41M market value, but just not the Best trainer, can only get about 2SP/day, with is bot enought to keep the star next year, for that you need 2,6SP/day.
Do not forget you received about 1,2 to1,65M depending the position you finish.

Whend i say Bet in the cup, try to go far, because you have a lot of abandoned Team in the league and in cup.