If we're to assume, and I'm sure some will disagree, that our strongest XI is:
Howard
Coleman Jagielka Stones Baines
Barry McCarthy
Mirallas Barkley Pienaar
Lukaku
Then it's really a matter of depth. Left wing would be priority for me, followed by keeper, followed by centre back. If we were to bring in say, Perisic or Milner on a free and Begovic, they would slot straight into the team. Then a centre back, who would immediately become third choice/challenge for a starting spot, say Reid on a free. Then I'd be looking to shore up centre mid. Delph would be my number one target and his contract expires very soon.
Begovic £12m???
Reid - Free
Delph - Free
Milner - Free
Obviously free doesn't mean free, but its better than paying a fee. Would not only improve the first team but add some real quality depth. Not sexy foreign names, but people should have learned by now (Barry/McCarthy) that they don't need to be.