I don't think that price would be similar to Coutinho's. I think Monaco would sel him for 80-90 million if we approach them early in the summer transfer window, while Liverpool just won't sell under 130-140 million (knowing their current transfer policy). Also if we indeed go for Griezmann (as is widely reported in the last few days), there is no way we can sign him and Coutinho (we would be looking at cca 230-240 million in transfers, which would mean we need to sell all of our deadweight (Paco, Arda, Rafinha, Aleix, Vermaelen, Gomes and maybe even Rakitić) and that is nearly impossible). I think the club should make their mind if they go for Griezmann/Lemar (cca 180-190) combo or Coutinho/another LW/ST combo e.g.
Martial or Werner (again around 180 million or cheaper).
I don't know how much money do we have left, But I'm presuming there is still cca 100 million from Neymar's sale and there is the yearly 60 million transfer budget. I doubt that we can sell any of our deadweights (except Rakitić) for more than 15 million. And there is also the transfer of Yerry Mina, which will probably be 10 million.