I enjoy the number crunching on fivethirtyeight.com, which is sometimes serious and sometimes just-for-fun. They recently tried to estimate how much money you’d have if you received a nickel every time someone in America said “if I had a nickel…” (The answer is $1.72 million, give or take, per year.) This made me wonder where the phrase came from.
UsingEnglish.com says “When someone uses this expression, they mean that the specific thing happens a lot. It is an abbreviation of the statement ‘If I had a nickel for every time that happened, I would be rich.'” I’ve seen variations that use a dime or a dollar.
Not many sites seem to tackle tracking down the origin of this phrase.
English Language & Usage says “the earliest I can find is Mark Twain in 1809.” Since he wasn’t born until 1835, this is suspect. My quick google search did not track down this alleged quote at any date. A search on Phrase Finder and Word Detective turned up nothing.
Do any of you have a source?