A person who “makes a mint” makes a lot of money—as if owning the mint. A classic joke about Life Savers candies is:
   
“Did you hear about the man who invented Life Savers? He made a mint.”
 
Clarence A Crane (1875-1931), of Garrettsville, Ohio, first invented Pep-O-Mint Life Savers peppermint candy in 1912, then sold the rights to Edward John Noble (1882-1958) in 1913 for $2,900, Crane made money, but it was Noble who made the “mint.”
 
“The man that invented life-savers made a mint” was cited in many newspapers in 1925, sometimes with the heading, “Our Worst Joke.”
     
“Did you hear about the man who invented Polos? They say he made a mint” is a similar joke about Polos Mints (popular in the United Kingdom).
 
   
Wikipedia: Edward John Noble
Edward John Noble (1882 - 1958, aged 76) was an American broadcasting and candy industrialist originally from Gouverneur, New York. He co-founded the Life Savers Corporation in 1913. He founded the American Broadcasting Company when he purchased the Blue Network in 1943 following the Federal Communications Commission’s (FCC) decree that RCA divest itself of one of its two radio networks.
 
Edward Noble was born in Gouverneur, New York and educated in the public schools. He attended Syracuse University and graduated from Yale in 1905.
 
In 1912, chocolate manufacturer Clarence Crane of Cleveland, Ohio invented Life Savers as a “summer candy” that could withstand heat better than chocolate. Since the mints looked like miniature life preservers, he called them Life Savers. After registering the trademark, Crane sold the rights to the peppermint candy to Edward Noble for $2,900. Instead of using cardboard rolls, which were not very successful, Noble created tin-foil wrappers to keep the mints fresh. Pep-O-Mint was the first Life Savers flavor.
     
20 June 1925, Bellingham (WA) Herald, “The Laugh Line,” pg. 6, col. 4:
Our Worst Joke.
The man that invented life-savers made a mint.
 
20 June 1925, Hayward (CA) Review, “The Office Cat” by Junius, pg. 2, col. 2:
The man that invented life-savers made a mint.
 
Google Books
The New Yorker
Volume 9
1933  
Pg. 14:
YOU’VE probably heard that crack about Life Savers — “the fellow who invented Life Savers made a mint.” Well, we went into that the other day, and he didn’t. His name was Clarence Crane, he was a Cleveland manufacturer of chocolates, and he didn’t make a mint. He made nine hundred dollars. It was the people who bought him out who made a mint; the present business, they say, is valued at around twenty million. It centres in Port Chester now, in a neat five- story building, surrounded by green grass and a strong peppermint smell.
 
Google Books
The Reader’s Digest
Volume 58  
1951  
Pg. 157:
One of the recurring wisecracks in Life Savers history runs, “The fellow who invented Life Savers made a mint.” Actually, all the inventor got out of it was $2900.
 
Google Books
Western Engineer
Volumes 48-50
1964
Pg. ?:
“The man who invented Lifesavers made a mint.”
 
Google Groups: alt.video.dvd
The Wizard of Oz - Help with special features?   
Scot Gardner
8/14/01
(...)
And did you know that the man who invented Lifesavers made a mint?
 
Google Groups: alt.humor.jewish
PUNS: 04-28-04 (Part 1)
Renee
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(...)
One wonders if the man who invented lifesavers really made a mint?
 
Twitter
Jay D.
‏@JaredofMo
Did you hear about the man who invented Life Savers? He made a mint.
8:11 AM - 15 Jun 2012
 
Twitter
babyboomerbaptist
‏@BbyBoomRbaptist
Didya hear about the guy who invented lifesavers?
He made a mint.
12:06 PM - 8 Apr 2015
 
Twitter
Planet John
‏@planetjohn99
Didya hear about the guy who invented lifesavers?
He made a mint.
6:34 AM - 9 Apr 2015
 
reddit
The Guy Who Invented “Lifesavers”? (self.dadjokes)
submitted October 16, 2015 by Raaju201
My dad literally told me this one last week: “Did you hear about the guy who invented Lifesavers? They say he made a mint.”