The Red Sox are going to pay up for Lester. Their starting pitching prospects took a nosedive this season, and it seems very clear how strong a need starting pitching is. The Yankees and Cubs will both be hard in on Lester, with both giving offers as high as 180-200, but I would imagine 140-160 would still be enough for the Red Sox to get him back here, if it includes an ironclad no-trade clause.
It is a s*** ton of money, and he'll probably only be worth it for half of the contract, but if this team wants to be competitive, it needs him.