BBE(i)
15 The first birth of every living thing which is offered to the Lord, of man or beast, is to be yours; but for the first sons of man payment is to be made, and for the first young of unclean beasts.
16 Payment is to be made for these when they are a month old, at the value fixed by you, a price of five shekels by the scale of the holy place, that is, twenty gerahs to the shekel.