27:1 The Lord spoke to Moses, saying, 2 “Speak to the people of Israel and say to them, If anyone makes a special vow to the Lord involving the valuation of persons, 3 then the valuation of a male from twenty years old up to sixty years old shall be fifty shekels  of silver, according to the shekel of the sanctuary. 4 If the person is a female, the valuation shall be thirty shekels. 5 If the person is from five years old up to twenty years old, the valuation shall be for a male twenty shekels, and for a female ten shekels. 6 If the person is from a month old up to five years old, the valuation shall be for a male five shekels of silver, and for a female the valuation shall be three shekels of silver. 7 And if the person is sixty years old or over, then the valuation for a male shall be fifteen shekels, and for a female ten shekels. 8 And if someone is too poor to pay the valuation, then he shall be made to stand before the priest, and the priest shall value him; the priest shall value him according to what the vower can afford.
9 “If the vow  is an animal that may be offered as an offering to the Lord, all of it that he gives to the Lord is holy. 10 He shall not exchange it or make a substitute for it, good for bad, or bad for good; and if he does in fact substitute one animal for another, then both it and the substitute shall be holy. 11 And if it is any unclean animal that may not be offered as an offering to the Lord, then he shall stand the animal before the priest, 12 and the priest shall value it as either good or bad; as the priest values it, so it shall be. 13 But if he wishes to redeem it, he shall add a fifth to the valuation.
14 “When a man dedicates his house as a holy gift to the Lord, the priest shall value it as either good or bad; as the priest values it, so it shall stand. 15 And if the donor wishes to redeem his house, he shall add a fifth to the valuation price, and it shall be his. (ESV)