"What exactly," I hear you ask is 'a snip'
"Snip" here is a British slang term recorded from the 1920s meaning a bargain or something surprisingly cheap. "Snip" has had other - conflicting - figurative senses down the centuries, including a swindle or deception, a sure thing, an insignificant person, and an easy task.
I'm not entirely sure what its origins are, but I thought it was an interesting phrase which over here we use without really thinking about it. Is this a term you are familiar with? Have you any idea how it originated?