Leviticus 27:1-6

The LORD said to Moses, “Speak to the people of Israel and tell them: ‘If someone makes a special promise to give a person as a servant to the LORD by paying a price that is the same value as that person, the price for a man twenty to sixty years old is about one and one-fourth pounds of silver. (You must use the measure as set by the Holy Place.) The price for a woman twenty to sixty years old is about twelve ounces of silver. The price for a man five to twenty years old is about eight ounces of silver; for a woman it is about four ounces of silver. The price for a baby boy one month to five years old is about two ounces of silver; for a baby girl the price is about one and one-half ounces of silver.