When I left my rented apartment, I wanted to take my mehudar mezuzos with me and replace them with simpler ones, but the new tenant asked me to leave them for him. I charged him $120 for each one.

Two months later, he took them to a sofer who told him that while they are nice, they are worth a maximum of $100 each. He then verified this with several sofrim. He now claims I cheated him and he wants a refund of the amount he was overcharged.

Q: Do I have to repay him?

A: Overcharging is called ona’ah (lit. exploitation). The halacha is that a buyer who overcharges a customer one-sixth of the item’s market value must refund the overcharge. An exception to the laws of ona’ah is the sale of land; one who overcharges in a sale of land is not obligated to a refund the overcharge (C.M. 227:29). The issue related to your question is whether something attached to the ground, the mezuzah on the doorpost, is categorized as land or retains its character as a movable item. If it remains a movable item, the laws of ona’ah apply, but if it is categorized as land once it is attached to a structure, the laws of ona’ah would not apply (C.M. 95:1). The matter is subject to debate; as such, the seller has the right to maintain that halacha follows the opinion that items attached to the ground are not subject to the halachos of ona’ah (also see 227:34).

There is, however, another dimension to this question. What is the halachic definition of “attached to the ground?” In other words, how permanent must the attachment be for it to become a part of the house? Does something attached with pegs become part of the structure, or is it necessary for the object to be more permanently affixed with cement? Some opinions maintain that items that are attached with pegs are included in the sale of a home (C.M. 214:11), but this is only because both the seller and buyer included the attached item with pegs as an integrated part of the sale. Since the issue of a sale relates to the intent of the seller and buyer, the attached item might be considered part of the sale of the house. However, in our case, since the sale relates only to the mezuzah attached with pegs, nails, or screws, and it is not an integral part of the structure, all opinions agree that it is considered a movable item and subject to the halachos of ona’ah.

Since the halachos of ona’ah apply, you should be required to refund the extra $20 (one-sixth of the purchase). However, Chazal expect a buyer to have the purchase appraised as quickly as possible to determine whether he was overcharged. In the event that one did not have the merchandise appraised in due time, it is assumed that he has forgiven his right to a refund (C.M. 227:7). In this case as well, although many people don’t remove mezuzos unless they are painting, it still would seem that since the buyer  had the option to have the mezuzos appraised right away and did not, he has forgiven his right to demand a refund of the overcharged $20 per mezuzah.