Bava Metzia 51A

משום הכי חזרו.

it is due to this reason that they reverted to following the statement of the Rabbis, as the sellers were in any event able to renege at any point, while R' Tarfon extended the period during which the buyers could renege on the transaction.

אלא אי אמרת מוכר נמי כלוקח דמי, מאי נפקא להו מינה? כי היכי דעבדי ליה רבנן תקנתא ללוקח, הכי נמי עבדי ליה רבנן תקנתא למוכר!

But if you say that the legal status of a seller is also limited like that of a buyer in terms of the period of time during which he may renege, what difference is there to the merchants? Just as the rabbis instituted an ordinance on behalf of a buyer enabling him to renege on the transaction, so too, the rabbis instituted an ordinance on behalf of a seller. If the time afforded to the seller is equal to the time afforded to the buyer, the fact that R' Tarfon extended this time would not be a reason for the merchants to revert to following the opinion of the Rabbis, as there is a benefit and a loss for the merchants according to both opinions.

תגרי לוד לא שכיח דטעו.

The Talmud answers: With regard to the merchants of Lod, it is rare for them to err, and therefore they preferred limiting the period during which the buyer could renege over extending the period during which they themselves could renege.

אושפיזכניה דרמי בר חמא זבין חמרא וטעה. אשכחיה דהוה עציב, אמר ליה: אמאי עציבת? אמר ליה: זביני חמרא וטעאי. אמר ליה: זיל הדר בך. אמר ליה: הא שהאי לי יותר מכדי שאראה לתגר או לקרובי! שדריה לקמיה דרב נחמן, אמר ליה לא שנו אלא לוקח, אבל מוכר ⁠– לעולם חוזר.

The Talmud relates: The landlord of Rami bar Ḥama sold a donkey and erred in fixing its price. Rami bar Ḥama encountered him and noticed that he was sad. Rami bar Ḥama said to him: Why are you sad? The landlord said to him: I sold a donkey and I erred in fixing its price. Rami bar Ḥama said to him: Go and renege on the transaction. The landlord said to him: I have waited more than the period of time that it takes for me to show the merchandise to a merchant or to my relative. Rami bar Ḥama sent the landlord before Rav Naḥman for a ruling and Rav Naḥman said to him: A baraita states this halakha only with regard to a buyer, but a seller may always renege on a transaction.