Chelsea's transfer policy in recent years seem more self-sufficient than I expected.
Sales (reported figures)
David Luiz: €50m
Mata: €45m
De Bruyne: €22m
loan fees from Lukaku, Moses, Romeu, Wallace: around €7m
that's €124m from the last summer and this already by selling players outside of first 11's. I think they can raise another €50m or more from the sales of R.Lukaku, V.Moses, Demba Ba, Marco Marin, Mikel if they wanted to and still have plenty players in 1st team, on loan and youth teams.