Well as has been said before, there's a fair amount of money freed up in wages from outgoings this season (Ramirez and Osvaldo, plus Davis off the books). If Koeman is expecting NO-ONE to be sold I think he's being a bit unreasonable - if we're offered £40million or more for Mane we'd have to take it, and I'd have faith in our recruitment to improve our team with that much money.
The thing he should be pushing for is every penny brought in to be made available for signings.