Numbers 18:16

16And their redemption price, from a month old you shall redeem, according to your 18:16 Since the price is set at five shekels, this term is not to be understood here as an ordinary appraisal (which could vary), but probably refers to the priest’s estimation of whether the item qualifies for redemption.valuation, for the [fixed] price of five shekels in silver, in accordance with the shekel of the sanctuary, which is twenty gerahs.