throw a sprat to catch a mackerel(redirected from one throws a sprat to catch a mackerel)
throw a sprat to catch a mackerel
To expend or risk a small amount of effort or money that has the potential to yield much greater benefits or rewards. A sprat is a much smaller fish than a mackerel, so you use the smaller as bait to catch the larger. When big retailers like them offer cash-back prizes, they are throwing a sprat to catch a mackerel—the money they make from sucking in customers more than outweighs what they spend in actual payouts.
Farlex Dictionary of Idioms. © 2015 Farlex, Inc, all rights reserved.