Leviticus 27:8-10

The Voice

⁸ If someone cannot afford these prices, then bring him to stand before the priest, and the priest will assess the situation and value him according to what the person can afford.

⁹ Whenever someone vows to give an animal that is acceptable as an offering to Me, then that animal is sacred and is the property of the sanctuary. ¹⁰ Whoever makes the vow should not switch one animal for another, a good animal for a bad, or vice versa. If someone does switch one for another, then both animals are considered sacred.