The priest must figure out the field’s value until the jubilee year. You will pay its value on that day as something holy, belonging to the Lord.
The priest will determine what its value is. The value will be whatever the priest decides.
But if you give the field after the jubilee year, the priest will estimate its value based on the number of years left until the next jubilee year.
You may give a field you bought (not one that was a part of your family property) to the Lord as something holy.
In the jubilee year the field will go back to the person from whom it was bought, to whom it belongs as family property.