When you 'll finish the 260' K stadium, you 'll get the
"never walk alone" achievement (playing a game in a full stadium, max lv).

Without spending extra T, you can have the complete stadium at lv 16-18.
At that time, you also have the fans of the team, to sell the tickets (in the right price).
After that, game over about this part.

the good thing is that you have some good money from the tickets (and from friendly games too)
and you don't have Mourinho braking your @@, when you 're not building something