Idiom: An Arm and a Leg Posted on 17th December 201822nd November 2018 by DoubleClick An Arm and a Leg: A large amount of money, very expensive or costly Example: New house cost in London to you will be an arm and a leg. Share this:Click to share on Twitter (Opens in new window)Click to share on Facebook (Opens in new window) Related Posted in Idiom and tagged idiom A.