Halakhah zu Wajikra 27:16

The commandment of appraising a field, that he give the appraisal specified in the section of the Torah: To rule in the laws of appraisal of fields - meaning to say that one who consecrates his field and wants to redeem it, that he should give the appraisal fixed in the section of the Torah - "the seed of a chomer of barley for fifty shekel-coins of silver" (Leviticus 27:16), for all of the years of the Jubilee [cycle], which are forty-nine years. And according to the exact calculation, the appraisal of the field that is fitting to plant a chomer of barley is a sela and a pundyon a year. As the shekel-coin stated in the Torah is called an undifferentiated sela in the language of the Sages; and the gerah that is stated in the Torah is the maah in the words of the Sages - and the Sages added a sixth upon the shekel-coin, that is called a sela, as we have said. And that sela is equal to four dinar, and a dinar is four maah, and a maah is two pundyon. It comes out [to] a sela and a pundyon for each year. As even though the sela is forty-eight pundyon according to this calculation of ours - nonetheless, one who wants to take a sela from a money changer, needs to give forty-nine pundyon so that the money changer will earn one pundyon. And since he has to give forty-nine pundyon [in this case], we calculate it according to the calculation of what the consecrator would pay the money changer - as the hand of (terms for) the consecrated is always upon the higher. And we appraise it the same if he consecrates a field so good that there is none like it in the land or a field so bad that there is none as bad as it. As Scripture did not want to distinguish in this matter and made [the same] appraisal for all lands (Arakhin 14a).