An arm and a leg

After God had created Adam he noticed that he looked very lonely.
He decided to help.
He said "Adam, I've decided to make you a woman.
She'll love you, cook for you, be sweet to you, and understand you."
Adam said "Great! How much will she cost me?"
The answer came back, "An arm and a leg."
"Well," said Adam "What can I get for a rib?"

(Note: arm and a leg: (idiomatic) A very high price for an item or service; an exorbitant price; usually used after the verb cost.)