Mishnayos Eruchin Perek 4 Mishnah 2

But with regard to offerings that is not so, as one who took a vow and said: It is incumbent upon me to provide the offering of this leper, to a leper who requires it for his purification; if the one undergoing purification was a destitute leper, the one who took the vow brings the offering of a destitute leper, which is one male sheep, a tenth of an ephah of fine flour, and two doves or two pigeons (see Leviticus 14:21–22). If the one undergoing purification was a wealthy leper, the one who took the vow brings the offering of a wealthy leper, which is two male sheep, a ewe, and three-tenths of a ephah of fine flour (see Leviticus 14:10). Rabbi Yehuda HaNasi says: I say: Even with regard to valuations it is so. He explains: For what reason does a destitute person who valuated a wealthy person give the valuation in accordance with the means of a destitute person? It is due to the fact that the wealthy person is not obligated to pay anything, as the debt was generated by the destitute person who vowed to donate the valuation of a wealthy individual. But in a case similar to that of the offerings of a leper, in the case of a wealthy person who said: It is incumbent upon me to donate my valuation, and a destitute person heard him and said: It is incumbent upon me to donate that which he said, the destitute person gives the valuation of a wealthy person. If when one took a vow of valuation he was destitute and he became wealthy, or if he was wealthy and became destitute, he gives the valuation in accordance with the means of a wealthy person. Rabbi Yehuda says: This is the halakha not only in a case where one was wealthy either at the time he took the vow or at the time of payment; even if when one took a vow of valuation he was destitute and he became wealthy and again became destitute, he gives the valuation in accordance with the means of a wealthy person.

אֲבָל בַּקָּרְבָּנוֹת אֵינוֹ כֵן. הֲרֵי שֶׁאָמַר, קָרְבָּנוֹ שֶׁל מְצֹרָע זֶה עָלָי. אִם הָיָה מְצֹרָע עָנִי, מֵבִיא קָרְבַּן עָנִי. עָשִׁיר, מֵבִיא קָרְבַּן עָשִׁיר. רַבִּי אוֹמֵר, אוֹמֵר אֲנִי אַף בָּעֲרָכִין כֵּן. וְכִי מִפְּנֵי מָה עָנִי שֶׁהֶעֱרִיךְ אֶת הֶעָשִׁיר נוֹתֵן עֵרֶךְ עָנִי, שֶׁאֵין הֶעָשִׁיר חַיָּב כְּלוּם. אֲבָל הֶעָשִׁיר שֶׁאָמַר עֶרְכִּי עָלָי, וְשָׁמַע הֶעָנִי וְאָמַר, מַה שֶּׁאָמַר זֶה עָלָי, נוֹתֵן עֵרֶךְ עָשִׁיר. הָיָה עָנִי וְהֶעֱשִׁיר אוֹ עָשִׁיר וְהֶעֱנִי, נוֹתֵן עֵרֶךְ עָשִׁיר. רַבִּי יְהוּדָה אוֹמֵר, אֲפִלּוּ עָנִי וְהֶעֱשִׁיר וְחָזַר וְהֶעֱנִי, נוֹתֵן עֵרֶךְ עָשִׁיר: