שוה שש בחמש מי נתאנה מוכר יד מוכר על העליונה רצה אומר לו תן לי מקחי או תן לי מה שאוניתני

an item worth six ma’a for five ma’a, who was exploited? It is the seller. Therefore, the seller is at an advantage. If he wishes, he can say to the buyer: Give me back my merchandise and nullify the transaction, or he can say: Give me back the sum which you received by engaging in exploitation of me.

איבעיא להו פחות משתות לרבנן לאלתר הויא מחילה או בכדי שיראה לתגר או לקרובו ואם תמצי לומר בכדי שיראה לתגר או לקרובו מאי איכא בין שתות לפחות משתות

§ A dilemma was raised before the Sages: According to the opinion of the Rabbis that one has only until a period of time has passed that would allow him to show the merchandise to a merchant or to his relative in order to claim that he has been exploited, in a case where the disparity between the value of the purchase item and the price paid is less than one-sixth, is there a waiver of the discrepancy and therefore the transaction is finalized immediately, or in this case as well, is the transaction finalized only after the time that it takes the buyer to show the merchandise to a merchant or to his relative? And in addition, if you say that the transaction is finalized only after the time that it takes to show the merchandise to a merchant or to his relative, what difference is there between a disparity of one-sixth and a disparity of less than one-sixth?

איכא דאלו שתות ידו על העליונה רצה חוזר רצה קונה ומחזיר אונאה ואילו פחות משתות קנה ומחזיר אונאה

The Gemara answers: There is a difference, as in the case of a disparity of one-sixth, the one who was exploited has the advantage, since if he wishes, he reneges on the transaction, and if he wishes, the buyer acquires the purchase item, and the one who perpetrated the exploitation returns the sum gained through his exploiting the other, while in the case of a disparity of less than one-sixth, the buyer acquires the purchase item, and the one who perpetrated the exploitation returns the sum gained through his exploiting the other, but there is no option of nullifying the transaction.

מאי תא שמע חזרו לדברי חכמים

The Gemara returns to the dilemma: At what point in time is a disparity of less than one-sixth between the value of the purchase item and the price paid waived? The Gemara suggests: Come and hear a resolution of the dilemma from the mishna: Rabbi Tarfon said to them: Throughout the entire day it is permitted to renege on the transaction and not merely for the period of time it takes to show the purchase item to a merchant or a relative. The merchants of Lod said to him: Let Rabbi Tarfon leave us as we were, with the previous ruling. They reverted to following the statement of the Rabbis.

סברוה פחות משליש לרבי טרפון כפחות משתות לרבנן דמי אי אמרת בשלמא פחות משתות לרבנן בכדי שיראה לתגר או לקרובו ולרבי טרפון כל היום משום הכי חזרו אלא אי אמרת פחות משתות לרבנן לאלתר הויא מחילה

The Gemara explains the proof. The Sages assumed that the legal status of a disparity of less than one-third according to the opinion of Rabbi Tarfon, who holds that one-third is the determinative disparity, is like a disparity of less than one-sixth according to the opinion of the Rabbis, who hold that one-sixth is the determinative disparity. Granted, if you say that in the case of a disparity of less than one-sixth according to the Rabbis the buyer can claim exploitation only in the time that it takes him to show the merchandise to a merchant or to his relative, and according to Rabbi Tarfon the transaction is finalized only after the entire day has passed, it is due to that reason that the merchants of Lod reverted to following the statement of the Rabbis, as there was some benefit to them in following the opinion of the Rabbis. But if you say that in the case of a disparity of less than one-sixth according to the Rabbis the waiver is in effect and the transaction is finalized immediately,