Give them Marrone on co-own. Oh, and Matri isn't a legit 20 goal a season striker. If he were, and consistent at that, he wouldn't be worth 12-15 million at best. We overpaid for him, and only we value him that much. I doubt other teams/clubs feel the same way.
Moreover, if Marotta really believes he can get any striker/cf/ss worth his salt for under 25 Million (remember, not all teams do player exchanges, especially outside Italy) then good luck with that. Guys like Damiao are already being valued at over 20 Million, and that's because the club doesn't need to sell (and there are many other clubs who can just tell us to fuck off and look elsewhere).
Suarez, RVP, Cavani, and even Dzeko will all cost 25+ Million, with the exception perhaps being RVP (given he is on the final year of his contract; even then, his wage demands will kill us).