If you've ever gone shopping with a lot of needs and $82,239,493 burning a hole in your trousers, you know how Jacksonville General Manager David Caldwell feels as the NFL heads into its free agent signing period Wednesday.

"The fun is to know you have it and it's at your disposal if you need it," Caldwell said of his league-high salary cap space. "But the challenge is to be able to find the players to spend it on. You can't create players to spend it on."

NFL fans should read that last line one more time, breathe and repeat. Just because the wallets runneth over doesn't mean your favorite team is going to pay chicken-salad salaries for … well, you know.

"The nature of free agency is you're going to overpay," Caldwell said. "If you want a player, you have to overpay to get him. That's the nature of the beast. And there's a limited pool of talented players. And there's a large of pool of money this year, especially in north Florida."

As newspapers and websites are wont to do, NFL.com was premature in listing its Top 99 free agents. By the time teams got done tagging and tying up the best players, NFL.com had lost seven of its top 12 free agents, including the top four.

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Of the players left over, 10 were labeled as difference makers. Fourteen more are labeled impact players. Of those 24 players, three are running backs, which generally generate lukewarm interest, while seven are on the wrong side of 30, which is a big no-no for the more sensible shoppers. So that's maybe a little more than a dozen players to get really excited about in the frantic first-wave of free agency. Maybe.

Now compare that with some of the massive amounts of salary cap room that's available. After the Jaguars, the 49ers have about $62 million and four more have between $50 million and $60 million. In the NFC North, the Bears are eighth at $46.5 million, followed by the Lions ($25.3 million), Vikings ($23 million before recent re-signings) and Packers ($20.8 million).

"You have to be cautious and look at why they're becoming free agents," 49ers General Manager Trent Baalke said. "A team has the money and financial commitment to do it, why aren't they doing it?

"Last year in Denver, they had Demaryius Thomas and Julius Thomas and were capable of only signing one."

Demaryius stayed and got paid. Julius went to Jacksonville and got overpaid.

It appears Broncos General Manager John Elway's pool of talent will be cherry-picked again after his defense dominated Carolina in Super Bowl 50. Linebacker Von Miller was given the franchise tag, but 26-year-old defensive tackle Malik Jackson and 25-year-old inside linebacker Danny Trevathan are among the most prized free agents available.

There's a reason Cam Newton looked like a mere mortal in Super Bowl 50. Every time the Panthers tried to establish their vaunted running game to take the heat off Newton, they were stonewalled by Jackson, Trevathan and their interior partners.

Much was made of how Elway used veteran free agency to add defensive starters DeMarcus Ware, T.J. Ward, Aqib Talib and Darian Stewart. But the other seven starters and the nickel corner were acquired by Elway via the draft or, in one case, right after the draft as a rookie free agent.

Since becoming Broncos GM in 2011, Elway, one of the best quarterbacks in NFL history, has used all five of his top picks on defenders who started or contributed to winning the Super Bowl. Meanwhile, Jackson and Trevathan were taken in the fifth and sixth rounds, respectively, in 2012.

Most GMs take a far more patient approach to free agency than their fans would like. Fans crave big-name gambles, even though, as Colts GM Ryan Grigson put it, "the house usually wins in free agency."

One of the more notoriously cautious general managers is Green Bay's Ted Thompson. He always stays the course as fans yelp with displeasure.

"We value free agency," Thompson said. "We have guys like Julius Peppers who we've signed as free agents.

"We're not opposed to doing that. In a perfect world, we've said all along that we'd like to draft, develop and keep our own players."

Asked if he'd change that philosophy if he sensed the window closing on his team, Thompson said no because philosophies should be deeply-rooted beliefs, not whims.

"No," he said, "we're not going to chase ghosts because we think the clock is ticking."

Mark Craig has covered the Vikings since 2003 for the Star Tribune. • mcraig@startribune.com