Matthew Poole and continuators on Leviticus 27:27

27 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.

(i. e.) If it be the first-born of an unclean beast, as appears from ver. 26. which could not be vowed, because it was a first-born, nor offered, because it was unclean, and therefore is here commanded to be redeemed or sold. Others understand it of all unclean beasts in general, and not of the first-born of them, because the first-born of such were to be redeemed by a sheep, Exod. 13. 13. without the addition of any such fifth part as is here enjoyned. Which is true of the first redemption of them, but then as after they were redeemed they might be again vowed unto God, so when the owners would redeem them a second time, it was but reasonable they should pay a better price for them. And if this were meant of unclean beasts in general, this were the very same law which is mentioned before ver. 11, 12, 13. which, it is not probable, would after a few verses be unnecessarily repeated again like a distinct law.

And the price thereof was given to the Priests, or brought into the Lords treasury.