I've heard the phrase "don't spend it [money] all in one store" a number of times, virtually always in a joking manner. Where did it originate from and has it always been said as a joke?
Google books says that the term originates from here's a ha'penny. The definition it gives for this is:
"A joking phrase that accompanies the gift of a small amount of money to someone, usually a child."
The origin and reasoning for this phrase can be seen in lots of different situations. Quite possibly one of the earliest examples of a situation that would of provoked this statement is the Prodigal Son.
The prodigal son runs off and spends all of his inheritance in a very short amount of time (all at once) and then is left with nothing. This results in him going back to his fathers house and falling on his mercy. Something not deemed desirable. Again lending itself to the saying "don't spend it all at once or in one place."
As Ryan suggests in an earlier answer, Eric Partridge, A Dictionary of Catch Phrases, second edition (2003) has this entry for "don't spend it all ...":
here's a ha'penny (or a penny): don't spend it all at one shop (or all at once) is a jocularity accompanying the munificent gift to a young child: late C19–20; by 1960, ob.; by 1970, virtually [defunct]. R,C. 1977, cites M. Page, Fast Company, c. 1936, for the ob. US var[iant] don't spend it all in one place. P.B.: and don't spend it all at once! is still a joc[ular] accompaniment in UK to the handing over of a very small sum, usu[ally] in change.
Partridge is wrong in thinking that the expression "don't spend it all in one place" is obsolete (or obsolescent) in the United States, however, as numerous Google Books matches for the phrase in books published in recent years indicate. The suggestion that "don't spend it all..." originated in the late nineteenth or early twentieth century is a bit inaccurate, too. A Google Books search finds a version of the expression in Benjamin Disraeli, The Wondrous Tale of Alroy. The Rise of Iskander, volume 2 (1833):
"True," said the eunuch ; "there is something in that. Here, boy, here is a piastre for you. I like to encourage men of science, and all that belong to them. Do not go and spend it all in one morning, boy, and when the fair captive is cured, if you remind me, boy, perhaps I may give you another."
The earliest Google Books match for the "don't spend it all in one store" variant is from Myrtle Reed, At the Sign of the Jack-o'-Lantern (1905):
"Dear Cousin Belinda," it read, "I hope you're taking pleasure in your hunt. I have kept my word to you and in this very room, somewhere, is a sum of money which represents my estimate of your worth, as nearly as sordid coin can hope to do. It is all in cash, for greater convenience in handling. I trust you will not spend it all in one store, and that you will, out of your abundance, be generous to the poor. It might be well to use a part of it in making a visit to New York. When you find this, I shall be out in the cemetery all by myself, and very comfortable. Yours, EBENEZER JUDSON."
"Don't spend it all in one place." occurs in the film version of Duddy Kravitz when someone tips him. He's telling Duddy to be careful with his money, I guess. Is it a translation of a Yiddish expression since I do associate with what Jewish people in North America say?
In 1865 17 year-old Michael de Young and his 20 year-old brother, Charles, wanted to start a newspaper in San Francisco. They borrowed and received "a twenty dollar gold piece and an admonition not to spend it all in one place and, more importantly, to return it within a week." They borrowed it from Captain William C. Hinkley, from whom their mother rented a flat. Their newspaper, the Daily Dramatic Chronicle, became the San Francisco Chronicle. Source - Gaudy Century The story of San Francisco's Hundred Years of Robust Journalism, pages125, 126, by John Bruce, Random House, 1948
As a small child in mid-(20th)century USA, I heard this expression from both my American father and my English mother, as well as various aunts and uncles--all Depression-Era kids. I have personally chosen to interpret the phrase as "spread the wealth," much like Dolly Levi in "Hello, Dolly!" who said, "Money is like manure...it doesn't do any good unless it is spread around, encouraging young things to grow."