Leviticus 27:1-8

“The Lord said to Moses, ‘Speak to the Israelites and say to them: “If anyone makes a special vow to dedicate persons to the Lord by giving equivalent values, set the value of a make between the ages of twenty and sixty at fifty shekels of silver, according to the sanctuary shekel, and if it is a female, set her value at thirty shekels. If it is a person between the ages of five and twenty, set the value of a male at twenty shekels and of a female at ten shekels. If it is a person between one month and five years, set the value of a male at five shekels of silver and that of a female at three shekels of silver. If it is a person sixty years old or more, set the value of a male at fifteen shekels an of a female at ten shekels. If anyone making the vow is too poor to pay the specified amount, he is to present the person to the priest, who will set the value for him according to what the  man making the vow can afford.” ‘ “