Tricky part with FA is the winner curse of FA. You are overpaying to win the auction, and for the most part the guys who get to UFA are at or past their peak. Trading is how you can get Josh Beckett at 25 years old (never mind his mixed career, that is still a super premium asset). It's how you could get Pedro Martinez at the BEGINNING of his era defining brilliance. An org is only as good as its own development machine, but a good part of that machine is developing currency to acquire guys.
Nabbing one of the premium pitching FAs this year is easier since for Price and Lester, all it costs is money. If the Red Sox want to win a bidding war, they can - there is no draft pick issue. For me, if you can snag one of the Lester-Scherzer-Price trio (at least) and perhaps one other solid arm, then you can look through your org depth and try to fill your #4/5 positions that way. Barnes, Kelly and Owens and De La Rosa all look like reasonable possibilities there. Workman and Webster could be dynamite late inning options, but their utility as starters is very very limited.