Before Eve, Adam is alone in the Garden of Eden. God comes and walks with Adam. God says, "Adam, I saw that you were lonely, so I created a woman, to be your wife. She'll help you in everything. Wash and mend your clothes, wash the dishes, keep the house clean, help raise your children, love you forever, be your best friend, and the best part is; She'll give you wonderful sexual pleasure".
Adam thanks the Lord. Then hesitates and asks: "Lord, how much will she cost me"?
God says: "An arm and a leg".
Adam hesitates again, and asks God: "What can I get for a rib?"