Support (Mishnah): They reverted to Chachamim's opinion.

Granted, if the seller can always claim, this is why they reverted to Chachamim's opinion (R. Tarfon gives them the same to claim as Chachamim, burned he gives more time to buyers than Chachamim do).

But if the buyer and seller have the same time, why did they revert? The extra time R. Tarfon gives (the whole day) helps also them!

Rejection: They reverted because they often overcharged, and rarely undercharged.

Rami bar Chama's host sold wine and was underpaid. He was sad, because the time to show it had elapsed. Rami sent him to Rav Nachman, who ruled that the seller can always claim.

Question: What is the reason?

Answer: The buyer holds the item. Wherever he goes, he can show it to people who will tell him if he erred;

The seller does not hold the item. He will not realize his mistake until another sale of that item arises.

Reuven was selling silk bands. He was asking for six, but they were worth five. If someone gave him five and a half, he would accept it. Shimon reasoned: if I pay five and a half, I cannot claim the Ona'ah (it will be too little)! He paid six and claimed the Ona'ah.

(Rava): One may claim Ona'ah only from a merchant, but not from a regular person selling his belongings. (It is known that one sells his belongings only for more than their value.)

A similar case occurred with a man selling nose rings. Rav Chisda ruled like Rava; Rav Dimi and R. Elazar approved.

Question (the coming Mishnah): Just like (one can claim) Ona'ah from a commoner, he can claim from a merchant.

Suggestion: 'Commoner' refers to a regular person selling his belongings.

Answer (Rav Chisda): The Mishnah discusses one selling hemp clothing, which is normally sold. The Kelim one uses are dear to him, and he sells them only for more than their value.

(Mishnah): Buyers and sellers are both forbidden to deceive. Just like Ona'ah applies to a commoner, it applies to a Tagar (professional merchant);

R. Yehudah says, Ona'ah does not apply to a Tagar.

The one who was deceived has the upper hand. (E.g. if it was the buyer,) he can demand back his money, or to be paid back the Ona'ah (what he overpaid).

(Gemara) Question: What is the source of this?

Answer (Beraisa): "V'Chi Simkeru Memkar... Al Tonu" teaches only when the buyer was deceived (overpaid);

"Oh Kano... Al Tonu" includes when the seller was underpaid.

The Torah must teach both.

Had it commanded only the seller, one might have thought that this is because he knows the item well, but the buyer is not so aware, so he is not commanded;

If it only commanded the buyer, one might have thought that this is because it is advantageous to buy, but selling is disadvantageous, so the seller is not commanded.

(Mishnah - R. Yehudah): Ona'ah does not apply to a Tagar.

Question: What is the reason?

Answer #1 (Rav Nachman): R. Yehudah discusses a Tagar who constantly buys and sells. He knows the value well, and sometimes he intentionally undercharges, when he wants money for a good purchase.

.Answer #2 (Rav Ashi): R. Yehudah means that the law of Ona'ah (i.e. a sixth) does not apply to a Tagar. Rather, he can demand compensation for any amount he was underpaid.

Support (for Rav Nachman - Beraisa): Ona'ah does not apply to a Tagar because he knows prices.

(Mishnah): The one who was deceived has the upper hand. (He can demand back his money, or to be paid back the Ona'ah.)

Question: Our Mishnah is not like R. Nasan, nor like R. Yehudah ha'Nasi (in the Beraisa on 50b)!

Our Mishnah says that the one who was deceived has a choice. This is unlike R. Nasan. (He holds that if Ona'ah is more than a sixth, the sale is void. If it is exactly a sixth, the Ona'ah is returned);

Our Mishnah says that the buyer has the upper hand (when he was deceived). Rebbi says that the seller has the upper hand!

R. Elazar: I do not know who taught this clause of our Mishnah!

Answer #1 (Rabah): Really, it is R. Nasan. Also the Beraisa should say that he can choose.

Answer #2 (Rava): Really, it is Rebbi. (He and our Mishnah both hold that whoever was deceived has the upper hand.) The Beraisa discusses the case that the Mishnah did not explain (when the seller was deceived).

Support (Rav Ashi): Our Mishnah says that the law is the same for the buyer and seller, but it illustrates only the buyer's claim.

(Rav): If Reuven sold to Shimon 'on condition that you have no claim of Ona'ah against me', Shimon can claim the Ona'ah;

(Shmuel): He cannot claim the Ona'ah.

Suggestion: Rav holds like R. Meir, and Shmuel holds like R. Yehudah.

(Beraisa - R. Meir): If Levi told Leah 'you are Mekudeshes to me on condition that you have no claim against me for food, clothing and (standard frequency of) Bi'ah', she is Mekudeshes, and his Tenai is void;

R. Yehudah says, the Tenai is valid regarding monetary matters (food and clothing).

Rejection #1: Even R. Yehudah could hold like Rav. R. Yehudah said that the Tenai works only when she knows what she is losing, for she pardons him. In the sale, Shimon does not know that there is Ona'ah, so he does not pardon it!

Rejection #2: Even R. Meir could hold like Shmuel. R. Meir said the Tenai is void only when it definitely uproots Torah law. In the sale, perhaps there is no Ona'ah (so the condition is valid)!

(Rav Anan citing Shmuel): If he said 'on condition that you have no (claim of) Ona'ah against me', he cannot claim Ona'ah;

If he said 'on condition that there is no Ona'ah', behold there is Ona'ah (he can claim it).

Question (Beraisa): If one buys and sells be'Emanah (Reuven pays Shimon to sell Reuven's goods for as much as he can), or he says 'on condition that you have no Ona'ah against me', there is no Ona'ah.

Rav said that both Tana'im hold like him. Like whom is the Beraisa?

Answer #1 (Abaye): Indeed, we must say that Rav holds like R. Meir, Shmuel holds like R. Yehudah.

Answer #2 (Rava): We need not say so. Rather, the Beraisa discusses one who explicitly said how much Ona'ah there is (the buyers knows, and he pardons it). Rav's law is when he said only 'on condition that...';

(Beraisa): (Either side can claim Ona'ah) when no one specified. If the seller said 'it is worth 100. I sell it to you for 200, on condition that you have no Ona'ah against me', he cannot claim Ona'ah;

Similarly, if the buyer said 'it is worth 200. I will buy it for 100, on condition that you have no Ona'ah against me', he cannot claim Ona'ah.

(Beraisa): If one who buys and sells be'Emanah, the owner may not say 'buy the good merchandise for yourself at its price (for which you will pay me later), and sell the bad for me' (the loan is compensation for his work. This is Ribis!) There are two options:

Shimon may buy both good and bad at its price (and keep the profits of what he sells);

Or, both are be'Emanah, and Reuven pays all Shimon's expenditures. He does not pay for Shimon's toil, for Shimon already received his full wage.

Question: Where did he receive this?

Answer (Rav Papa): The Beraisa discusses selling hemp garments. The retailer normally keeps four percent of each sale.

(Mishnah) Question: How much can a Sela lack, and one (who gives it for a Sela) does not transgress Ona'ah?

Answer #1 (R. Meir): It can lack up to four Isarim, one Isar per Dinar;

Answer #2 (R. Yehudah): It can lack up to four Pundeyonim, one Pundeyon per Dinar.

Answer #3 (R. Shimon): It can lack up to eight Pundeyonim, two Pundeyonim per Dinar.