Leviticus 27:8

ואם מך הוא BUT IF HE POOR so that his means are not sufficient to pay this valuation, והעמידו THEN THEY SHALL PRESENT HIM — the person made the subject of a valuation, לפני הכהן BEFORE THE PRIEST, and the priest shall set a value on him according to the means of him who promised the valuation (Sifra, Bechukotai, Section 3 14). על פי אשר תשיג ACCORDING TO HIS ABILITY — i. e. according to what he possesses shall he (the priest) assess him (the person who has promised the valuation), leaving him sufficient to live upon: a bed, mattress and cushion and tools necessary for his trade; thus, in respect to the latter, if he was an ass-driver (earning a living by carrying loads) he has to leave him his ass (Arakhin 23b).

But if he be too poor for the estimated value, then he shall present himself before the priest, and the priest shall value him; according to the ability of him that vowed shall the priest value him.

וְאִם־מָ֥ךְ הוּא֙ מֵֽעֶרְכֶּ֔ךָ וְהֶֽעֱמִידוֹ֙ לִפְנֵ֣י הַכֹּהֵ֔ן וְהֶעֱרִ֥יךְ אֹת֖וֹ הַכֹּהֵ֑ן עַל־פִּ֗י אֲשֶׁ֤ר תַּשִּׂיג֙ יַ֣ד הַנֹּדֵ֔ר יַעֲרִיכֶ֖נּוּ הַכֹּהֵֽן׃ {ס}