The Tampa Bay Buccaneers signed Vincent Jackson to a five-year, $55 million deal as an unrestricted free agent in 2012 but they probably didn't expect him to play all five years of that contract. Veteran contracts of that length rarely go the distance, but Jackson, one of the best free agent signees in franchise history, was indeed a Buccaneer through 2016.
That same 2012 free agency class brought Carl Nicks to town, and at the time that signing was considered a major coup. Not only did the Buccaneers get one of the NFL's best guards in his prime, but they stole him from a division rival after the New Orleans Saints were forced to use their franchise tag on Drew Brees.