There is a halakhic principle that when one purchases an item, the payment of the money does not effect the transaction. The transaction is effected only by means of the buyer’s physically taking the item into his possession, e.g., by pulling the item. Payment of money by the buyer creates only a moral obligation for the seller to sell him the item. When two types of currency are exchanged for each other, one of the types will have the status of the money being paid, and the other will have the status of the item being purchased. Handing over the former will not effect the transaction, while handing over the latter will. The mishna teaches: When one purchases gold coins, paying with silver coins, the gold coins assume the status of the purchased item and the silver coins assume the status of money. Therefore, when one party takes possession of the gold coins, the other party acquires the silver coins. But when one party takes possession of the silver coins, the other party does not acquire the gold coins. In an exchange of silver coins for copper coins, when one party takes possession of the copper coins, the other party acquires the silver coins. But when one party takes possession of the silver coins, the other party does not acquire the copper coins. In an exchange of flawed coins for unflawed coins, when one party takes possession of the flawed coins, the other party acquires the unflawed coins. But when one party takes possession of the unflawed coins, the other party does not acquire the flawed coins. In an exchange of an unminted coin for a minted coin, when one party takes possession of an unminted coin [asimon], the other party acquires a minted coin. But when one party takes possession of a minted coin, the other party does not acquire an unminted coin. In an exchange of a coin for movable property, when one party takes possession of the movable property the other party acquires the coin. But when one party takes possession of the coin, the other party does not acquire the movable property. This is the principle: With regard to those who exchange all forms of movable property, each acquires the property of the other, i.e., the moment that one of the parties to the exchange takes possession of the item that he is acquiring, e.g., by means of pulling, the other party acquires the item from the first party.
How so? If the buyer pulled produce from the seller, but the buyer did not yet give the seller their value in money, he cannot renege on the transaction, but if the buyer gave the seller money but did not yet pull produce from him, he can renege on the transaction, as the transaction is not yet complete. But with regard to the latter case, the Sages said: He Who exacted payment from the people of the generation of the flood, and from the generation of the dispersion, i.e., that of the Tower of Babel, will in the future exact payment from whoever does not stand by his statement. Just as the people of those generations were not punished by an earthly court but were subjected to divine punishment, so too, although no earthly court can compel the person who reneged to complete the transaction, punishment will be exacted at the hand of Heaven for any damage that he caused. Rabbi Shimon says: Anyone who has the money in his possession has the advantage. The Sages said it is only with regard to the seller that payment of money does not effect a transaction, so that if the buyer paid for the item and did not yet take possession of the purchase item, the seller can renege on the sale and return the money. By contrast, once the buyer paid for the item he cannot renege on his decision and demand return of his money, even if he did not yet take possession of the purchase item.
The measure of exploitation for which one can claim that he was exploited is four silver ma’a from the twenty-four silver ma’a in a sela, or one-sixth of the transaction. Until when is it permitted for the buyer to return the item? He may return it only until a period of time has passed that would allow him to show the merchandise to a merchant or to his relative who is more familiar with the market price of merchandise. If more time has elapsed he can no longer return the item, as the assumption is that he waived his right to receive the sum of the disparity. The mishna continues: Rabbi Tarfon ruled in Lod: Exploitation is a measure of eight silver ma’a from the twenty-four silver ma’a of a sela, one-third of the transaction. And the merchants of Lod rejoiced, as this ruling allowed them a greater profit margin and rendered the nullification of a transaction less likely. 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, and they reverted to following the statement of the Rabbis in the mishna with regard to both rulings.
Both the buyer and the seller are subject to the halakhot of exploitation. Just as the halakhot of exploitation apply to a layman, so do the halakhot of exploitation apply to a merchant. Rabbi Yehuda says: There is no exploitation for a merchant, as he is an expert in the market price of merchandise. The one upon whom the exploitation was imposed has the advantage. If he wishes, he can say to the other: Give me back my money and nullify the transaction, or he can say: Give me back the sum that you gained by exploiting me.
How much can the sela coin be eroded through usage, and its use in a transaction at its original value will still not constitute exploitation? Rabbi Meir says: The accepted depreciation is four issar, which is a rate of one issar per dinar, or one twenty-fourth of a dinar. And Rabbi Yehuda says: The accepted depreciation is four pundeyon, which is a rate of one pundeyon per dinar, or one-twelfth of a dinar. And Rabbi Shimon says: The accepted depreciation is eight pundeyon, which is a rate of two pundeyon per dinar, or one-sixth of a dinar.
The mishna continues: Until when is it permitted for one to return a worn coin once he realizes that it is defective? In the cities [bakerakim], one may return it only until a period of time has passed that would allow him to show it to a money changer, who is an expert in matters of coins. In the villages, where there is no money changer, one may return it only until Shabbat eves, when people purchase their Shabbat needs. Although these are the limits of how much a coin must be eroded in order for there to be exploitation, if the one who gave the coin to the aggrieved party recognized it, he must accept it back from him even after twelve months have passed no matter how little the erosion affected its value. And he has only a grievance against him, as the Gemara will explain. And one may give the slightly eroded coin for use in the desacralizing of second-tithe produce and he need not be concerned, as one who would refuse to accept a slightly eroded coin is merely a miserly soul, while the coin is in fact valid for any use.
The measure of exploitation is four silver ma’a from the twenty-four silver ma’a of a sela. And the smallest monetary claim in court for which a plaintiff can obligate a respondent to take an oath is two silver ma’a. And the smallest monetary admission for which that respondent takes the oath is an admission that one owes at least the value of one peruta. On a related note, the tanna adds that there are five halakhic situations involving perutot: The admission to part of a claim must be that one owes at least the value of one peruta, and a woman is betrothed with the value of one peruta. And one who derives benefit of the value of one peruta from consecrated property has misused consecrated property and is liable to bring an offering, and one who finds an item that has the value of one peruta is obligated to proclaim that he found it. And with regard to one who robs from another an item that has the value of one peruta and took an oath to him that he robbed nothing, when he repents and seeks to return the stolen item he must take it and follow its owner even to Medea. In that case, he may not return the item by means of a messenger; he must give it directly to its owner.
In this mishna, as in the previous one, the tanna enumerates several halakhot that share a common element. There are five halakhic situations where one-fifth is added to the value of the principal, and these are they: A non-priest who eats either teruma, or teruma of the tithe, which the Levite separates from the first tithe and gives to a priest, or teruma of the tithe of demai, or ḥalla, or first fruits; in each of these cases, he adds one-fifth when paying restitution to the priest who owned the produce. And one who redeems his own fruit of a fourth-year sapling or second-tithe produce adds one-fifth. One who redeems his own consecrated property adds one-fifth. One who derives benefit worth one peruta from consecrated property adds one-fifth. And one who robs the value of one peruta from another and takes a false oath in response to his claim adds one-fifth when paying restitution.
These are matters that are not subject to the halakhot of exploitation even if the disparity between the value and the payment is one-sixth or greater: Slaves, and documents, and land, and consecrated property. In addition, if they are stolen, these items are subject neither to payment of double the principal for theft nor to payment of four or five times the principal, if the thief slaughtered or sold a stolen sheep or cow, respectively. An unpaid bailee does not take an oath and a paid bailee does not pay if these items were stolen or lost. Rabbi Shimon says: With regard to sacrificial animals for which one bears responsibility to replace them, they are subject to the halakhot of exploitation, as this responsibility indicates a certain aspect of ownership. And those for which one does not bear responsibility to replace them, they are not subject to the halakhot of exploitation. Rabbi Yehuda says: Even in the case of one who sells a Torah scroll, an animal, or a pearl, these items are not subject to the halakhot of exploitation, as they have no fixed price. The Rabbis said to him: The early Sages stated that only these items listed above are not subject to the halakhot of exploitation.
Just as there is a prohibition against exploitation [ona’a] in buying and selling, so is there ona’a in statements, i.e., verbal mistreatment. The mishna proceeds to cite examples of verbal mistreatment. One may not say to a seller: For how much are you selling this item, if he does not wish to purchase it. He thereby upsets the seller when the deal fails to materialize. The mishna lists other examples: If one is a penitent, another may not say to him: Remember your earlier deeds. If one is the child of converts, another may not say to him: Remember the deeds of your ancestors, as it is stated: “And a convert shall you neither mistreat, nor shall you oppress him” (Exodus 22:20).
One may not intermingle produce bought from one supplier with other produce, even if he intermingles new produce with other new produce and ostensibly the buyer suffers no loss from his doing so. And needless to say, one may not intermingle new produce with old produce, in the event that the old produce is superior, as with grains, since intermingling lowers its value. Actually, they said: With regard to wine, they permitted one to mix strong wine with weak wine, because one thereby enhances it. One may not intentionally mix wine sediment with the wine, but one may give the buyer wine with its sediment; the seller is not required to filter the wine. One who had water mix with his wine may not sell it in the store, unless he informs the buyer that it contains water. And he may not sell it to a merchant, even if he informs him of the mixture, as, although he is aware that there is water mixed with the wine, it will be used for nothing other than deceit because the merchant will likely not inform the buyer that it is diluted. In a place where they are accustomed to place water into the wine to dilute it and everyone is aware of that fact, one may place water in the wine.
The prohibition against mixing different types of produce applies only to an individual selling the produce of his field. By contrast, a merchant may take grain from five threshing floors belonging to different people, and place the produce in one warehouse. He may also take wine from five winepresses and place the wine in one large cask [pitom], provided that he does not intend to mix low-quality merchandise with high-quality merchandise. Rabbi Yehuda says: A storekeeper may not hand out toasted grain and nuts to children who patronize his store, due to the fact that he thereby accustoms them to come to him at the expense of competing storekeepers. And the Rabbis permit doing so. And one may not reduce the price of sale items below the market rate. And the Rabbis say: If he wishes to do so, he should be remembered positively. One may not sift ground beans to remove the waste, lest he charge an inappropriately high price for the sifted meal, beyond its actual value; this is the statement of Abba Shaul. And the Rabbis permit doing so. And the Rabbis concede that one may not sift the meal only from the beans that are close to the opening of the bin to create the impression that the contents of the entire bin were sifted, as this is nothing other than deception. One may neither adorn a person before selling him on the slave market, nor an animal nor vessels that he seeks to sell. Rather, they must be sold unembellished, to avoid deceiving the buyer.