In terms of money-making, this game is pretty straightforward, and easy in a way.

For lower level managers with players base price not hitting 127m yet, 18-21yo 75%+ players bought in week 1 should be improved to 90%+ by end of season, granting a net gain value of roughly 55%-60% as a 1-season player. This ratio should be universal across all levels.

And then each free 18yo free youths from Youth Academy should also be improved by 20% in the first season, and when sold, should gain the equivalent amount to buy a 21yo 75% player for the following season. This ratio is also the same in all level. So it is just about training youths properly for a few seasons to set the finance straight.

For higher level managers with players base price at 127m or higher, money can easily be earned by playing friendlies using reserve players. Again, max 3 seasons of taking up 4 youths per season would do the job. The % price loss from players sold should be just a tiny fraction of friendlies income in a full season when 3 could be played each day by reserve players alone after tpb training.

Level 1-5 managers are those who face the hardest hurdle in finance, with youth facility not being built in full yet (less youths), stadium would only be earning measly ticket income and also prize money from winning trophies can just barely cover the price of 1 more player.