Just don't sign any old farts anymore. No to Icardi, Auba, Laca and whoever else is being mentioned. Especially if they are on high wages already.
Scamacca has he papers to be a proper striker one day. However he needs at least one year at Sass to develop there, probably even two. We should watch him but for now please stay away.
Considering the options we have right now, I'd assume that the direct replacement will be Kean. In reality though there will be none, it's up to Morata, Dybala and Chiesa to step up. They are the leaders now. Add on top of that Kulu the new lolzillian Kaio Jorge, Cuadrado and of course the mentioned Kean. It looks more than enough to me.
I wish we spent some good amount for a midfielder though. We're fucking stacked there, so we also need to sell unfortunately.
In worst case scenario just save up the money for next year. It's about time we spend the cash in a wise way, buying pieces that the team is missing. Believe me, there will be need for spending next Summer too.