Regarding money to buy players... let's say we have an established revenue of 270M/year now.
Of these, around 220M are for wages + fee installments.
As reports say, we have already reached that level, considering we pay a lot of installments every year and we are still paying for the likes of Bonucci, Quagliarella, Matri, Giovinco, Isla, Asamoah, Litch, Caceres, Vidal, Ogbonna, Tevez, etc. This means that before we sign new players, we have to let some of them go, at least to shed salary off. We cannot increase our spending this year.
Next year we will be able to spend some money, as part of these fee installments will be gone and our revenue should increase 30/50M.
The salaries and value of some players who aren't useful anymore are:
Vucinic - 3M net - 6M/year; (value around 5M)
Quagliarella - 2.1M net - 4.2M/year; (value around 4M)
Giovinco - 1.4M net - 2.8M/year; (value around 6M)
Isla - 1.4M net - 2.8M/year; (value around 6M)
Pepe - 1.3M net - 2.6M/year; (no value because of injuries)
De Ceglie - 1.3M net - 2.6M/year; (value around 3M)
Peluso - 0.8M net - 1.6M/year; (value around 3M)
Padoin - 0.7M net - 1.4M/year; (value around 2M)
Motta - 0.6M net - 1.2M/year. (value around 1M)
If Marotta is successful in shipping these guys away for their current value and not needing to pay part of their salaries, the total saved would be of around 25M in salaries only. Plus increase of 30M in revenue from sales. If these sales are received in 2 installments it equals 15M revenue.
If you include Immobile and Zaza's sales both paid in 2 installments it makes a total of 25M saved in salaries + 22M increase in revenues by sales.
It makes a grand total of 47M to spend this year with new players signings = 1st installments + annual salary.
If we for example signed Sanchez for 30M in 3 installments and a net 5M wages his annual cost would be of 20M.
This money would be enough to sign one great player and a few other good players, with lower salaries. That may be the reason why they are chasing young players.
So even without being able to actually spend money, we can have a decent mercato. But it completely depends on Marotta's ability to sell our players, specially Vucinic, Quags, Giovinco, Isla, Pepe, De Ceglie. Not even for a high price, but just for a small but fair price and without having to keep paying part of their salaries.