Of course the first three were traded for first -- but all were available because they wanted to get paid. Upon reflection, even at the time, Pedro and Schilling didn't cost a haul, just some young pitchers with potential.
The Beckett trade cost the Sox their top prospect, Hanley Ramirez, who was an instant star in the NL. But Boston won the World Series...
Some also may argue Lackey was a top mound prize at the time of his signing. Sale, another mega-trade, definitely was... especially -- ironically now -- his contract was such a steal when he was acquired.