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The amount of dollars true NFL heavyweight teams throw down on splashy signings in the first hours of free agency isn't what separates them from the pack. No, it's their ability to find key contributors during the second and third waves.

Take, for example, the two teams that are playing in Super Bowl LII on Sunday.

The Philadelphia Eagles offense has a backfield with many moving parts. One is running back LeGarrette Blount, who was a short-yardage and goal-line bruiser during critical games late in the 2017 season. He scored six rushing touchdowns over the Eagles' final seven contests, including the playoffs. Blount didn't sign with Philly until May and played under a contract that paid him just $900,000.

The other team has Rex Burkhead. The New England Patriots running back finished the regular season with 518 yards from scrimmage and eight total touchdowns over only 10 games, all while getting paid just $1.8 million.

There are plenty of opportunities for similar bargain-bin diving in 2018. Jerick McKinnon could be the next running back to make a major contribution at little cost. Others, such as tight end Tyler Eifert and wide receiver Jordan Matthews, come with clear injury concerns, but that will be reflected in their value on the open market, making any gamble well worth the risk.

Here's a look at the best likely bargains available at every position.