Leviticus 27:1-10

Again, the LORD spoke to Moses, saying, “Speak to the children of Israel and say to them, ‘When a man makes a special vow [consecrating himself or a member of his family], he shall be valued according to your [established system of] valuation of people belonging to the LORD [that is, the priest accepts from the man making the vow a specified amount of money for the temple treasury in place of the actual person]. If your valuation is of a male between twenty and sixty years of age, then your valuation shall be fifty shekels of silver, according to the shekel of the sanctuary. Or if the person is a female, then your valuation shall be thirty shekels. If the person is between five years and twenty years of age, then your valuation for the male shall be twenty shekels and for the female ten shekels. But if the child is between one month and five years of age, then your valuation shall be five shekels of silver for the male and three shekels for the female. If the person is sixty years old and above, your valuation shall be fifteen shekels for the male, and ten shekels for the female. But if the person is too poor to pay your valuation, then he shall be placed before the priest, and the priest shall value him; according to the ability of the one who vowed, the priest shall value him. ‘Now if it is an animal of the kind which men can present as an offering to the LORD, any such that one gives to the LORD shall be holy. He shall not replace it or exchange it, a good for a bad, or a bad for a good; but if he does exchange an animal for an animal, then both the original offering and its substitute shall be holy.