(and) that ain't hay

And that's significant. Often used in reference to an amount of money. He got a $5,000 bonus this year, and that ain't hay.

Inf. That is not a small amount of money. (The highly informal word ain't is built into the expression.) I paid forty dollars for it, and that ain't hay! Bob lost his wallet with $200 in it—and that ain't hay.

That's a great deal, especially of money; also, that's important. For example, He's making ten thousand a month, and that ain't hay. Originally used to describe a sum of money that is large, this phrase was later extended to other circumstances, as in She married a titled lord, and that ain't hay. [Colloquial; first half of 1900s]

People say and that ain't hay after an amount of money to emphasize that it is a large amount. For 13 out of the last 20 years Canadian bonds produced returns of more than 10%, and that ain't hay.

That’s a lot; also, that’s important. This American colloquialism, with its ungrammatical “ain’t” for “isn’t,” dates from the first half of the 1900s and at first was used mainly to describe a large amount of money. It was used in this sense in the motion picture The Killers (1946), where a character says, “I’m out ten G’s and that ain’t hay for me these days.” But it was also extended to other matters. Thus, a 1994 television serial, Sally Jessy Raphaël, had it: “Seven husbands! That ain’t hay!”