An Arm and a Leg

We use the term an Arm and a Leg to talk about something expensive. Why an arm and a leg? I have no idea. Why not a kidney and a liver? Maybe an arm and a leg are too valuable?

Here's an example:

"Joe paid an Arm and a Leg for that Apple iPhone 10. He paid $900 for it when it first came out" We can also say he got ripped off if we want to use a phrasal verbs.