Leviticus 27:23-27

Then the priest shall reckon unto him the worth of thy estimation, even unto the year of the jubile: and he shall give thine estimation in that day, as a holy thing unto the LORD.

In the year of the jubile the field shall return unto him of whom it was bought, even to him to whom the possession of the land did belong.

And all thy estimations shall be according to the shekel of the sanctuary: twenty gerahs shall be the shekel.

Only the firstling of the beasts, which should be the LORD’s firstling, no man shall sanctify it; whether it be ox, or sheep: it is the LORD’s.

And if it be of an unclean beast, then he shall redeem it according to thine estimation, and shall add a fifth part of it thereto: or if it be not redeemed, then it shall be sold according to thy estimation.