Q. I have two she’eilos revolving around the same issue:
1. My 9 year-old son received a new MP3 player from his grandfather for Chanukah. A few days later, I asked him if I could use his old one, and he told me that he had sold it to his friend for $5.00. I told him to get it back from him, because he cannot sell anything without my permission. May we void the sale?
2. This same son has a card collection, which he trades with his friends. In one such trade, he gave his friend a few cards in return for a single card. He later regretted making this deal. May he renege on the trade?
A: Since your son is a minor — under the age of bar mitzvah — the Torah does not recognize any transaction he makes, even if the MP3 player belongs to him. Chazal estimated that a minor does not have enough daas (grasp of reality) to be able to engage in commerce. Even a particularly astute child may not engage in commerce as a minor. The age limitation is a halachah l’Moshe miSinai (see Shu”t Chasam Sofer, Yoreh Dei’ah 317).
But Chazal recognized the need for children to engage in commerce if they must support themselves, so they validated a sale (of anything other than real estate) made by such a minor, from the age of “onas hape’utos” (see Gittin 59a and Shulchan Aruch, Choshen Mishpat 235:1). They extended this validity even to cases where the child does not need this particular sale in order to support himself (ibid., according to the ruling of the Ramban).
The age Chazal set for this is six or seven, depending on the child’s aptitude (some Rishonim write that females always mature younger than males, so the age is six for a girl and seven for a boy — see Nimukei Yosef, Gittin 59a; cf. Kesef Hakodashim 235:14). There are several opinions regarding up to what age we must test the child to determine whether he understands how business is transacted (see Rema 235:1 with Sma 3).
The child’s sale is valid even if it involved ona’ah (exploitation), as long as the amount overcharged or undercharged was less than a sixth of the item’s actual value (Choshen Mishpat 235:3; see Nachal Yitzchak 66:24, s.v. Uvagittin). Furthermore, the sale is considered final even if the ona’ah was more than a sixth, but the amount of time in which one is allowed to void the transaction on the basis of the ona’ah has elapsed (Giddulei Shmuel, Bava Metzia 49b). For the buyer (who overpaid), this is the amount of time it takes to show the object to an expert or a relative who knows the value of such an object (Choshen Mishpat 227:7). For the seller, it is until he comes across a similar object for sale and realizes that he was underpaid (ibid. 227:8).
These halachos do not apply to your case, however, because Chazal established these halachos out of concern for minors who had to support themselves. If a child has a guardian (apotropus) overseeing his finances, Chazal did not see a need to allow him to engage in commerce without the consent of his guardian (Kesubos 70a; Choshen Mishpat 235:2). Certainly when a child’s father is supporting him, he may not sell anything without his father’s consent (see Darkei Moshe 235:3 with Nesivos 10; Aruch Hashulchan 235:1 &10-11; cf. Shulchan Aruch Orach Chaim 658:6 and Shu”t Minchas Yitzchak 5:65).
In addition, certain objects belong to the father, not the child, and it is obvious that the child may not sell them without his father’s consent (see Choshen Mishpat 270:2 with Chiddushei R’ Akiva Eiger). Had your son been an adult and the object been his, he would not be permitted to cancel the sale unless the ona’ah was more than a sixth and the claim was made within the applicable time frame delineated above (see Choshen Mishpat 227:2,7-8).
Given all of the above, although your son has passed onas hape’utos, you may void the sale even if there was no ona’ah. This is certainly true if the object he sold belongs to you, but it is also the case if it belongs to him — assuming that you are supporting him.
Regarding the card collection, since you allow your son to trade cards, it appears that a specific trade cannot be voided now that your son regrets it. The halachah is that if a minor engaged in commerce and sold an object (as opposed to real estate) or gave a gift, if the apotropus approved the transaction, it is final (Choshen Mishpat 235:2). Seemingly, the same would apply if the apotropus gave prior consent to engage in such dealings. Obviously, then, if you, as his father, agreed to allow him to trade cards, and certainly if they belong to you and you consent to his commercial transactions, then those transactions are final.
