Leviticus 27:11-12 "Then he shall present the animal before the priest and the priest shall value it"

A person may want to make a donation to the service of HaShem equal to the value of a non-kosher animal or an animal that may not be sacrificed.

He is to consult the priest to evaluate the animal according to specific Torah guidelines.

The amount that the priest determines the animal to be worth will be the amount that the donor must contribute.