If it is an unclean animal, then he is to buy it back according to your valuation, and add a fifth of the value to it. But if it is not redeemed, then it is to be sold according to your valuation.
“Nevertheless, no devoted thing which a man sets apart from all that he has for Adonai, whether man or animal, or from the field of his possession, may be sold or redeemed. Every devoted thing is most holy to Adonai.
He is to make restitution for that which he has done wrong in regard to the holy thing, and is required to add a fifth part to it, and give it to the kohen. So the kohen will make atonement for him with the ram of the trespass offering—and he will be forgiven.