NFL free agency is right around the corner, and a bunch of lucrative contracts are sure to come with it -- some bigger than others, a few worth genuine excitement, most of them unlikely to deliver on their offseason promise. Nothing backs up the volatility -- the unpredictability -- of free agency -- like a look back at NFL history.

As the 2020 signing period approaches, let's take a look back at some of the best, worst and biggest deals of the last decade. Each year should serve as a clear reminder that free agency is just as, if not more, of a boom-or-bust proposition as the NFL's next biggest offseason event -- the draft. And depending on which team you root for, it should have you doubly excited (or worried) about the big spending that could be on tap for this spring.

2019

Best: DE Shaquil Barrett (Buccaneers)
Biggest: DE Trey Flowers (Lions, $90M total); QB Nick Foles (Jaguars, $22M per year)
Worst: RB Le'Veon Bell (Jets)

Barrett may very well be a one-year wonder, but for just $4 million in 2019, he gave the Buccaneers a ton of sacks -- 19.5, to be exact. At the very least, he showed Tampa it might have found a long-term pass-rushing answer for Todd Bowles' defense. Foles, meanwhile, is going to hurt Jacksonville financially, but Bell is an even worse investment and at a far less important position, even if his failings are in part due to his supporting cast.

2018

Best: WR Allen Robinson (Bears)
Biggest: QB Kirk Cousins (Vikings, $84M total, $28M per year)
Worst: CB Trumaine Johnson (Jets)

Robinson has been one of, if not the, most reliable components of the Bears' offense since coming aboard in the wake of Alshon Jeffery's departure. It's not his fault he's had Mitchell Trubisky and Chase Daniel throwing to him. If Chicago is smart, they'll make sure he's still the No. 1 target for whoever is taking snaps at quarterback in 2020. Johnson, on the other hand, was an absolute train wreck of a splash signing, and people could see that from the jump. He was good before, at times, but never, ever worth $72.5 million.

2017

Best: CB Stephon Gilmore (Patriots)
Biggest: CB A.J. Bouye (Jaguars, $67.5M total); DE Calais Campbell (Jaguars, $15M per year)
Worst: WR Kenny Britt (Browns)

The Patriots didn't get Gilmore from their rival Bills for cheap, dishing out $65 million over five years, but they've gotten exactly what they paid for -- lock-down coverage. Credit Gilmore's play on the outside for a good chunk of New England's success in recent Super Bowl runs. You probably forgot about Britt, didn't you? The guy got $32.5 million from Cleveland, only to catch all of 18 balls in nine games.

2016

Best: G Brandon Brooks (Eagles)
Biggest: DE Malik Jackson (Jaguars, $90M total); QB Brock Osweiler (Texans, $18M per year)
Worst: QB Brock Osweiler (Texans)

Like Gilmore, Brooks wasn't exactly a bargain, but he's already earned an extension in Philly because of his quiet dominance on the interior of the line, helping pave the way for the Eagles' 2017 Super Bowl win. Osweiler, meanwhile, was literally traded along with draft picks in exchange for cap relief because of how sickening his salary was for Houston. How far the Texans have come since then, hunting for a good QB.

2015

Best: C Rodney Hudson (Raiders)
Biggest: DT Ndamukong Suh (Dolphins, $114M total, $19M per year)
Worst: CB Byron Maxwell (Eagles)

We don't usually credit the Raiders for good front-office moves, but they struck gold on Hudson, prying him from the Chiefs for a pretty penny but then reaping the rewards of Pro Bowl play up the middle. Suh was certainly and predictably a letdown for Miami considering his lofty salary, but at least Miami had money to blow. Maxwell was even worse because of his billing as an up-and-coming shutdown corner, going to Miami (sound familiar?) in a salary dump the following year.

2014

Best: S Malcolm Jenkins (Eagles)
Biggest: CB Aqib Talib (Broncos, $57M total); CB Darrelle Revis ($12M per year)
Worst: S Jairus Byrd (Saints)

Byrd was the consensus top safety on the market in 2014, and a lot of people thought the Eagles should've paid up for him rather than take a gamble on Jenkins, who was a mid-tier hybrid at that point in his career. Turns out Philly made the right choice, with New Orleans eating a bunch of wasted money and the Eagles watching as Jenkins evolved into their own title-winning leader, both on and off the field.

2013

Best: DE Michael Bennett (Seahawks)
Biggest: WR Mike Wallace (Dolphins, $60M total, $12M per year)
Worst: WR Mike Wallace (Dolphins)

Bennett might get flak nowadays as an outspoken journeyman of sorts, but by returning to Seattle after a brief stop in Tampa Bay back in 2013, he helped shore up the Seahawks' defensive line for a couple of Super Bowl runs. As for Wallace, the speedster ended up making a fine career for himself with the Ravens, but not before proving to be too much of a one-trick pony in Miami, where his glitz as a big-money target never paid off.

2012

Best: QB Peyton Manning (Broncos)
Biggest: QB Peyton Manning (Broncos, $96M total, $19.2M per year)
Worst: QB Matt Flynn (Seahawks)

John Elway proved that you can buy your way to victory if the person you're buying just happens to be one of the greatest quarterbacks of all time. Manning obviously was a shell of himself by 2015, when Denver actually won it all, but he also gave Broncos fans some of the best years of their lives. Flynn did the opposite in Seattle, though his failed development ultimately paved the way for Russell Wilson.

2011

Best: RB Darren Sproles (Saints)
Biggest: CB Nnamdi Asomugha (Eagles, $60M total, $12M per year)
Worst: CB Nnamdi Asomugha (Eagles)

Sproles will never be regarded as one of the game's all-time greats at his position, but he deserves every bit of Hall of Fame consideration he'll get for his multipurpose production, and a lot of his legend was built as one of Drew Brees' favorite targets. Asomugha, on the other hand, wasn't nearly as awful as people like to pronounce, but the hype he got coming into Philly was absolutely unmatched.

2010

Best: DE Julius Peppers (Bears)
Biggest: DE Julius Peppers (Bears, $91.5M total, $15.25M per year)
Worst: OL Shawn Andrews (Giants)

Plenty of pundits railed against Chicago for breaking the bank to get Peppers, but the pass rusher pretty much ended up living up to his contract before returning to Carolina. There were plenty of other failed signings in 2010, but Andrews did less than almost all of them, inking a six-year, $32 million deal after a polarizing career with the Eagles, then making just seven starts in between back problems before hanging up the cleats.