My eight-year-old son confided to me that he had traded an album of “rebbi cards” – which I gave him as a reward – for a Slurpee. He now realizes that it was a foolish transaction. He’d like to pay his friend for the value of the Slurpee and reclaim his album, reversing the sale.

Q: Does he have the right to do this?

A: It would seem that your issue is the fact that the Slurpee your son received in exchange for the album is worth significantly less than the album, and the exchange should be nullified due to a violation of ona’ah (exploiting). Shulchan Aruch (227:4) rules that a buyer who is overcharged more than a sixth of the item’s market value has the right to cancel the sale. Accordingly, you would like to claim that the discrepancy between the value of the Slurpee and the album would cross the line of ona’ah and the exchange should be cancelled. This claim isn’t valid because the laws of ona’ah do not apply to bartering (exchanging objects). Sema (227:35) explains that when two people barter, they are not involved in a sale, since each party is interested in acquiring the object he needs. Since your son was more interested in the Slurpee than the album at the time of exchange, the deal is binding.

There is, however, a reason why the exchange can be reversed. According to the Torah, a minor does not have the ability to execute a transaction.

[Gittin 59a mentions that Chazal allow children who have an understanding of the value of objects (i.e. he can differentiate between a stone and a nut) to make transactions. He is capable of buying, selling, and even giving gifts (Choshen Mishpat 243:15). This allowance is limited to orphans who do not have a guardian and must obtain their basic needs of food, clothing, etc. (Choshen Mishpat 235:2.  See Nesivos HaMishpat 235:10 regarding a child who has a living parent).]

Therefore, when your child made an exchange with his friend, it was not a transaction recognized in halacha, and the transaction can be reversed. Another important factor is the discussion found in the Poskim if a parent’s gift to a child becomes the possession of the child or if it halachically remains the property of the parent. If it were to remain the property of the parent, the child would certainly not be able to exchange the album for the Slurpee (See Rema Choshen Mishpat 270:2 with commentary of R’ Akiva Eiger and Machaneh Ephraim Zechiah U’Matanah siman 2).

Q: What is considered "defective merchandise" according to halacha?

A: Defining "defective merchandise" depends on social norms and the nature of the sale.

According to the Shulchan Aruch, "Anything that the area's people agree is a defect that invalidates this sale can be returned; anything that they agree is not a defect cannot be returned… because whoever buys and sells relies on the local practice (C.M. 232:6)." Nowadays, there is strong emphasis on quality control. Many defects would invalidate a sale. This depends on whether the item is marketed as high-quality or cheap.

A regular book with one misprinted, albeit readable line would probably not be considered "defective" (although the printer would have to provide a proper patch for those lines); if a line is missing from the book, that is a defect. A cheap pen that sometimes writes poorly would not be considered defective, while an expensive pen would. A piece of furniture that is noticeably scratched would be considered defective.