Chelsea are unlikely to want to sell him in the first place but if they were willing then I don't think a club like Everton would be able to afford him. I did once see him go to Dortmund for like 17M in the second season, but that was a rare case.
On my Evteron save i got Lukaku for 25m efter the season loan. And that first season i even won the primer lague and he was the top scorer. As mention above i his a total beast. I use the Supreme Tottenham tactic and he scores like 35-45 goals in the league every season. My attack looks like:
I would have thought it was pretty much impossible. But for 25m I guess it would work.
I've done a couple of Everton saves and after the first season Chelsea either don't want to sell, or won't sell to a divisional rival. If you got in his favoured people list and Everton did well and Chelsea went rubbish. Maybe that could be a realistic way to get him through - not that you have much control over Chelsea's position...