"Quick change" is a form of the Short Con in which the Hustler confuses a cashier into giving more change than they should. The most lucrative quick change technique is the "progressive", in which smaller denomination bills are thrust back at the cashier for consolidation into a higher denomination. "Here, give me a five for these ones." (then, while holding the five and the ones...) "Oh, wait. Go ahead and give me a 10. Let me see... one, two, three, four and five is .. yeah, a 10. Thanks."
If you were paying attention, that was five dollars becoming 10. A quick change artist can keep that rolling until he ends up walking away with a $100 bill.
An alternate technique is to pay for something cheap with a $100 bill, accept the change, and then offer to pay with a smaller bill. The object is to confuse the cashier into giving back the $100 bill without remembering to take back the change.
Yet another method is to show the cashier a large bill in your hand, but use sleight of hand to actually hand over a smaller bill. If the cashier doesn't look at it before putting it into the till, they'll give back more change than you deserve.
Naturally, the best way to avoid these schemes is by being cool, calm, nice and slow.
Not to be confused with the theatrical term for a very fast costume change. Nor the 1990 Bill Murray film.
Josť Carioca manages to get into the World Cup for free by responding to the cashier's request for money with a complaint that he hasn't gotten his change back yet. Joe takes the ticket and runs off while the cashier contemplates his statement.
An episode of the Finnish RPG-themed comic Peluri combined this with poking fun at D&D's complicated monetary system. After some back-and-forth involving copper, silver, gold, platinum and electrum pieces, the guard the conman was paying toll to ends up having to sell his weapon and armour to him.
Art Sansom's The Born Loser had the title character, Brutus Thornapple, confronted by a man who asked if he had change for a seven dollar bill. Brutus gives him two ones and a five. Only after the quick change artist has left does Brutus, with seven dollar bill in hand, realize what happened.
An old Abbott and Costello routine does a variation relying on Abbott's fast talk and Costello's stupidity. "Could you give me two 10s for a five?"
As a variant, Abbott gets a few dollars off of Costello by counting 10 dollars in a non-standard fashion.
Abbott: All right, all right, I owe you $10, right? Costello: Yeah, that's right. Abbott: Right. 1, 2, 3. Say, how long were you in the Navy? Costello: Six years. Abbott: Six years! Well done you, six years. 7, 8, 9, 10. [Costello tries it a moment later, but has trouble when the mark has been in the Navy 90 days.]
Demonstrated in great detail in the film Mercy Streets. Particularly strange because Mercy Streets basically exists to be mild Christian propaganda; one would think the filmmakers would have been a little more concerned about showing easily-imitable criminal acts.
The film The Grifters has an example of the third type of con. The protagonist holds up a $20 bill but actually pays with a $10 bill.
Juan does this trick at the beginning of Nine Queens. After succeeding, he tries again at the same shop with a different cashier, only minutes later. Naturally, he is recognized and exposed.
Done several times in Paper Moon, such as when Moses purchases ribbons for Addie and rapid-talks the befuddled clerk out of several dollars.
In the novel American Gods, Mr. Wednesday casually pulls a variant of this, involving a credit card as well as cash, on a gas-station attendant. The exact details aren't mentioned, however: Neil Gaiman once stated in an interview that he'd deliberately tried to obfuscate the details of the cons used in the book, to prevent anybody from trying to replicate them in real life. (Didn't actually work, though. One of the bigger cons in the book was successfully replicated by a Canadian fan, who walked away with more than $6,000...)
The Howdunit series of writers' help books had "Pros and Cons", which details this con (among others.)
Frank Abagnale, Jr.'s, book The Art of the Steal, details the con, with pictures, to warn people what to look out for.
The novel Matchstick Men uses the change con during a sequence where Roy is teaching his newly met daughter Angela how to con people. Note that this scene was omitted in the film adaptation.
Live Action Television
Cheers: Harry the Hat uses this as a Short Con on Coach. Asking Coach to break a $20 into 20 $1 bills, Harry casually mentions other numbers while Coach is counting out the change so he gets much more than $20 back.
Harry also short changes Cliff in a similar manner.
Done every which way in Hustle; whenever they pay for their drinks the barman is going to be left with less money than he started with. And he knows this, and still can't work out how it happens.
The Real Hustle demonstrates how to make it work in real life, usually on store cashiers, and how not to fall for it.
Inadvertantly Inverted on Late Night With David Letterman where Larry "Bud" Melman is sent out in a silly costume to get two fives for a ten and, getting himself confused, goes around offering two tens for a five.
The 2nd edition Dungeons & Dragons sourcebook The Complete Thief's Handbook. The end of Chapter 6 had a story that illustrated the second type of con, which they called the "short-change swindle".