N'jie is £10m plus add ons, apparently. And I reckon Berahino will eventually go for no more than £20m.
So that's £30m, really.
On the flip side, we've already earned some £15-20m more from player sales than we've spent thus far this summer. And we're still likely to sell Soldado (£10m?); Lennon (£5-8m); Adebayor (maybe for nothing, maybe for up to £5m, but at least a large chunk of wages off costs). It's also possible that we will sell Townsend (£10-15m) and / or Carroll (£5m?).
It's furthermore true to say that we are scarily short of proper striker options.
So not only can we easily afford both Berahino and N'jie (and a proper DM), we also need them both. N'jie is supposedly as good as signed. And all sorts of sources seem to be saying that it's only a matter of time before we sign Berahino too.
So I'd be very surprised now if we didn't sign both.