A football team has four downs to make a first down (get ten yards), or else the ball turns over to the other team. The third down has been called the “money down” because if the first down is not made, the offensive team usually elects to kick (either a punt or a field goal try) on fourth down. Third down is the “money down” for both offense and defense.
 
“Money down” became popular in the 1980s and 1990s, probably as a result of the popularity of the term “money shot.” “Third down is the money down in football, the down where both the offense and the defense play with their backs to the wall,” sportswriter Steve Duin stated in The Oregonian (Portland, OR) on November 3, 1985. “I want to be a good third-down quarterback. That’s the money down. That wins games,” Michigan quarterback Brian Griese said in October 1997.
     
   
Google Books
Confessions of a Dirty Ballplayer
By Johnny Sample, with Fred J Hamilton and Sonny Schwartz
New York, NY: Dial Press
1970
Pg. 91:
... team had a third-down situation — the big money down — the quarterback very seldom threw to the man I was covering.
 
3 November 1985, The Oregonian (Portland, OR), “Arizona effectively handcuff OSU on third-and-whatever” by Steve Duin, pg. E1, col. 1:
Third down is the money down in football, the down where both the offense and the defense play with their backs to the wall.
 
3 October 1997, Indianapolis (IN) Star, “A Student of the Game: When it comes to calling the shots on the playing field, Michigan quarterback Brian Griese is his father’s son” by Phil Richards, pg. D1:
“That’s one area I study hard going into a game,” said Griese, a fifth-year senior who will call the signals Saturday, when 3-0 Michigan visits 1-3 Indiana (11:20 a.m., WTTV-4). “I want to be a good third-down quarterback. That’s the money down. That wins games.”
 
29 October 2000, Greenville (SC) News, “USC comes up short on Tennessee’s last drive” by Willie T. Smith III, pg. C6:
“It’s extremely frustrating,” said (South Carolina defensive end Kalimba—ed.) Edwards. “If we had won the game we’d be in control, still on top of the SEC. But things happen. We lost. We have to move on. ... We have a job to do and we didn’t do it. We had them third down so many times. We call third down the money down and we didn’t get paid.”
   
Google Groups: alt.sports.football.pro.dallas-cowboys
Keep On Keeping On
fgoodwin
12/20/07
(...)
Mickey Spagnola
DallasCowboys.com Columnist
December 20, 2007 7:26 PM
(...)
You’re darn right, especially on third down, the money down in this game. Heading into the Philadelphia game the Cowboys were converting 48.1 percent of their third downs. Nine of 13 games they converted at least 45 percent of their third downs
 
NFL.com
Breaking down ‘the money down’ for NFL defenses
By Pat Kirwan NFL.com
Published: June 19, 2009 at 03:15 p.m. Updated: July 26, 2012 at 08:22 p.m.
Every NFL defense works hard to get its opponent to third down. If they aren’t successful on third down, however, their efforts were for naught. When a team’s first and second down defense is effective, it opens things up for the designated pass rusher and the nickelback.
 
Twitter
Gabe Correa
‏@OrangeTint
Ohio U defense: They call third down “money down,” and Ohio University’s opponents certainly cashed in last fall. http://tinyurl.com/ntxdr5
7:08 AM - 10 Jul 2009
 
Twitter
Josh Vitale
‏@AUBlog
Bell called third down “the money down:” “If you can’t get off the field on third downs, it makes it hard to win games.”
7:46 PM - 18 Sep 2011
   
Cleveland.com 
Third down’s the charm: Ohio State defense improving on “money down” after early failures   
By Doug Lesmerises, cleveland.com
on October 15, 2014 at 4:50 PM, updated October 15, 2014 at 8:07 PM
COLUMBUS, Ohio—Third down was to be Chris Ash’s time to shine.
 
Twitter
Ryan King
‏@RKingGator
Third down = The money down.
7:24 PM - 25 Mar 2015
 
The Independent Florida Alligator
Third down is indeed the money down for the Gators’ defense
By Jordan McPherson, Alligator Staff Writer Oct 12, 2015
The signs are present on the field.
 
On third down, UF assistants jump up and down, holding posters with dollar signs high into the air as they work to pump up the crowd.
 
To the Gators, third down is money down, the time for them to prove their worth.
 
Twitter
bruce nichols
‏@brucenichols
Often when I am watching a football game and it’s third down, I can hear Kyle Boblitt saying, “Money down”. Good times on the sidelines.
1:02 PM - 28 Nov 2015
 
Blogging the Boys (Dallas Cowboys)
Cowboys News: Why Dak Prescott Has The Cowboys Offense Humming On “The Money Down”
By VAfan @vafanbtb Sep 21, 2016, 4:00a
(...)
Dallas Cowboys: Sturm: Cowboys rookie Dak Prescott handles third down like a veteran - Bob Sturm, DMN
The money down in the NFL is clearly third down. We have written for years how this team is dependent on Tony Romo to move the chains on a regular basis. In 2014, the Cowboys were second in the NFL on third-down conversions (just a shade behind the New Orleans Saints and Drew Brees and just a shade above the Green Bay Packers and Aaron Rodgers) at 47.3 percent. Phenomenal work from the offense.
 
Blogging the Boys (Dallas Cowboys)
Why Second Down Is The Money Down For The Dallas Cowboys
The Cowboys lead the NFL in third-down conversions, but what happens on second down may be even more important for the success of the 2016 offense.
by One.Cool.Customer @OCC44 Oct 13, 2016, 12:30p
(...)
Importantly, converting on second down allows teams to avoid third downs altogether, and for the 2014 Cowboys, this was a critical component to their high-flying offense: the 2014 team achieved 127 first downs from second down situations, but only 95 from third down situations.