Prohibition of interest

Many thanks to the rabbi for the quick response.
If nothing is specified except the prices, for example:
• Price for 30 days: 100
• Price for 60 days: 101
Is there an interest problem in this situation?

Usually, between professionals in the industry, the conduct is carried out in an abbreviated and concise manner, because transactions are conducted on a daily basis.
With us, people ask what the price is and always try to argue about it. Usually, the price is lowered. Sometimes the seller insists on his price and says that this is the last price for that item.
However, a fundamental question arises: When there is no clear market price, where does the halakhic line cross?
Ostensibly, it can be argued that many items do not have a “market price”.
For example:
• A professional, such as an electrician, offers pricing that varies between service providers and even varies according to negotiations with the customer.
• Even in cases such as purchasing computers for the office, the supplier offers a high price that is adjusted through negotiation, or different suppliers have different prices.
Can the price also be considered a ”market price”.”?

There are opinions that yes and some that no. Since this is a rabbinic prohibition (because it is a sale and not a loan) there is room for leniency.
Almost nothing today has a market price. The same goes for the examples you gave.

Thanks for answering my previous questions.
While reading the answers, I had a few more questions about interest:
1. Selling to customers abroad ” Deferring payment to the supplier:
We export goods to customers abroad, and sometimes customers request a specific product. In such cases, I agree with my supplier that he will give us the product here in Israel and we will ship it to our customer abroad, with the understanding that the customer may return the product within 30 days. If the customer does not return it, I pay the supplier within 60 days from the date of delivery.
Since in this case it is a kind of loan of a product for the purpose of sale, is it permissible to offer the supplier a reduced payment if I pay him within 45 days?
2. Payment in dollars versus shekels – Concern about interest:
In the case where a supplier gives me a price in dollars, but we agree that payment will be made in shekels in 60 days, according to the representative exchange rate on the day the invoice is issued - is there a concern about the prohibition of interest?
3. Library fines - is there interest in this?
The municipal library has begun collecting fines for late return of books. Does paying such fines constitute a prohibition of interest?
4. Regarding the market price - if there is any good advice, what is considered a market price product.
I can also argue that toilet paper does not have a market price, since in Shufersal it costs X, while in Rami Levy it costs Y, etc.

1. I didn't understand why you claim it's a loan. You're not giving him back the product, but its price, right? If you offer not a reduced price, that proves it's a sale and not a loan. You're essentially giving him responsibility for the sale. Even if you were to give him back the product itself, in my opinion it's still a sale with responsibility and not a loan.
2. There are different opinions on that, but in my opinion there's no problem with that. It's actually a payment in dollars, but you're transferring the dollars to him through their shekel value. This can be likened to lending a sah for a sah, and this is a rabbinic prohibition that has various permits. What's more, here it's a sales fee.
3. What does this have to do with interest? It's a penalty for latecomers. You also don't pay a reader's fee according to the Library Law. It's just a fine and not interest on anything else.
4. I think that almost no product today has a market price, unless there's a government law on the matter.
Here I saw someone who wants to claim that you can sue based on the price of a basket of products: https://www.toraland.org.il/%D7%9E%D7%90%D7%9E%D7%A8%D7%99%D7%9D/%D7%9B%D7%9C%D7%9B%D7%9C%D7%94-%D7%95%D7%9E%D7%A9%D7%A4%D7%98/%D7%9B%D7%9C%D7%9B%D7%9C%D7%94-%D7%95%D7%94%D7%9C%D7%9B%D7%94/% D7%90%D7%95%D7%A0%D7%90%D7%94-%D7%91%D7%99%D7%9E%D7%99%D7%A0%D7%95-%D7%9E%D7%91%D7%95%D7%A1%D7%A1%D7%AA-%D7%9E%D7%95%D7%A6%D7%A8-%D7%90%D7%95-%D7%A1%D7%9C-%D7%A7%D7%A0%D7%99%D7%95%D7%AA/
I disagree with him, because the basket also has no market price.
There are claims that even if there is a range of prices in the market, it is forbidden to sell beyond the highest price, but this claim also seems problematic to me. First, there is no market price here and in such a case there is no fraud. Secondly, according to this, whoever sets the most expensive price has always violated a prohibition, so why should I, who comes after him, consider him?!

1. We write the document in the following style
Document: Confirmation of the terms of the transaction
Date: 1/12/2024
Product price: $500
Terms:
We may return the product within 30 days of the date of purchase. If the product is not returned on time, we will be obligated to pay its price within 60 days of the date of delivery.
I accept the product on loan, with the option to sell it to my customer.
Even then, the Rabbi understands that it is okay to argue with the seller and say that I am willing to pay $450 on the 45th day during negotiations.
2. Price varies according to the exchange rate:
I agree that the price depends on an exchange rate that is not known in advance, neither by the buyer nor by the seller. Since the exchange rate varies and is not fixed in advance, there is no problem of interest in this case.
3. Penalties for late return of an item:
A similar principle can be applied to additional items. For example, if I lend my printer to my neighbor, I can make him sign a contract that requires him to return the printer within 48 hours. If he does not meet the condition, he will be fined 5 NIS for each day of delay.
According to the rabbi, this is not interest, since the fine is for the damage caused by the delay and is not related to the value of the object itself.
Early payment discount:
However, I found a similar question on the “Kav website Halacha:

https://kavhalacha.co.il/%D7%90%D7%A7%D7%98%D7%95%D7%90%D7%9C%D7%99%D7%94-%D7%91%D7%94%D7%9C%D7%9B%D7%94/%D7%93%D7%99%D7%A0%D7%99-%D7%9E%D7%9E%D7%95%D7%A0%D7%95%D7%AA/%D7%94%D7%90%D7%9D-%D7%99%D7%A9-%D7%90%D 7%99%D7%A1%D7%95%D7%A8-%D7%A8%D7%99%D7%91%D7%99%D7%AA-%D7%91%D7%AA%D7%A9%D7%9C%D7%95%D7%9D-%D7%9E%D7%A8%D7%90%D7%A9-%D7%A2%D7%9D-%D7%94%D7%A0%D7%97%D7%94-%D7%94%D7%A8%D7%91-%D7%9E%D7%A9%D7%94-%D7%99%D7%95%D7%A1%D7%A3

The website claims that it is prohibited to request a discount for catering services when the raw materials are not in the seller's possession at the time of placing the order.
However, according to the Rabbi, in the event that there is no fixed price for catering and the parties are allowed to negotiate the price, it can be argued that this does not constitute a prohibition on usury.
Did I understand correctly?
(I am Ashkenazi)

1. I understand that ”I am receiving the product on loan” is not the wording of the document but your interpretation of what is written in it. But that is not what I think. You are receiving it for consignment for sale and not on loan. The argument between you is about the premium you are entitled to for your consignment. And if that is the wording in the document itself, then change it.
3. I did not understand what the connection between this question and our discussion is. A fine for returning a book in a library is not interest in any sense. What is the principal that this is the interest on? Where is the loan or sale here? In the case of catering, there is a principal.

Hello Honorable Rabbi,
I wanted to think about the things that the Rabbi wrote the other day and see if it sharpens.
I come from the field of jewelry and diamonds and deal with the shipment of goods abroad.
The method I saw is actually called MEMO
I asked
ChatGpt
to define what MEMO is for me and I received the following answer
“Receipt of goods in MEMO” (Memo) is a common commercial method in the diamond and jewelry industry, in which goods are delivered to a customer (usually a wholesaler, retailer or business partner) without immediate purchase, but rather on the basis of an agreement that the goods will be returned if they are not sold or are not found suitable.
Principles of MEMO:
1. Ownership remains with the supplier: The goods are not sold but are loaned, so the supplier remains the owner until sold or returned.
2. Purpose of inspection: The customer receives the goods to present them to end customers, to check for suitability or to check quality.
3. Limited time period: The memoranda process is defined for a fixed time, at the end of which the customer is required to return the goods or pay for them if they sold them.
4. Agreed in advance: A memoranda agreement usually includes a written document that details the terms of the loan, the value of the goods, and the terms of return or payment.

In light of the things I have noted when I agree in advance on the price and payment dates and I receive the goods in memoranda, is there no concern about interest here?
I am deliberately emphasizing the point because it is very important for me to understand how to conduct myself in a business sense.

Regarding my note about the catering from the link Next
https://kavhalacha.co.il/%D7%90%D7%A7%D7%98%D7%95%D7%90%D7%9C%D7%99%D7%94-%D7%91%D7%94%D7%9C%D7%9B%D7%94/%D7%93%D7%99%D7%A0%D7%99-%D7%9E%D7%9E%D7%95%D7%A0%D7%95%D7%AA/%D7%94%D7%90%D7%9D-%D7%99%D7%A9-%D7%90%D7%99% D7%A1%D7%95%D7%A8-%D7%A8%D7%99%D7%91%D7%99%D7%AA-%D7%91%D7%AA%D7%A9%D7%9C%D7%95%D7%9D-%D7%9E%D7%A8%D7%90% D7%A9-%D7%A2%D7%9D-%D7%94%D7%A0%D7%97%D7%94-%D7%94%D7%A8%D7%91-%D7%9E%D7%A9%D7%94-%D7%99%D7%95%D7%A1%D7%A3
the goal This was just to show that the rabbi there thinks that payment for catering, which apparently has no market price because it can change, is a concern for interest.
But if I understood the rabbi, there is almost no market product today, but only a product for supervision.

What you described clearly says what I wrote that you do not own the goods here but the original seller owns them. He defines that it is loaned to you, although I am not sure that is the definition. You are his messenger to sell the item. Either way, it is not a loan.
Regarding catering, it does not say there is a market price. There is a price from the caterer, and he gives a discount compared to his own price for advance payment. And when you have goods of the same type, even if the quantity is small, there is no prohibition here (in catering, he discusses when you have goods but the consumer is not interested in them now because they are getting old, and opinions were divided on this too).

First of all,
Thank you to the rabbi for the response.
I am glad to hear that there is no loan here, and therefore I am not violating the prohibition of interest, even if I leveraged it to get a better price due to the early payment.
I had a feeling that it was not, but I wanted to be on the safe side.
Is it possible to make a kind of transaction permit for my entire business so that I have halachic insurance that I am not violating anything?

The point I tried to convey through the post about catering that does not have a market price?
According to what I learned from the rabbi in the previous post, almost everything except a government-supervised product is a product that does not have a market price.
So why did the rabbi enter there (on a website that deals with catering) into the whole consideration of whether he has such a product or not? He simply replied that it is a price that does not have a market price, and therefore there is no interest issue here.
What did I miss?

Regarding the example of the library and the printer, can we say that every fine is not interest?
For example, the electric company, if I am late in paying, I have interest expenses
(I assume that companies that increase their prices have a transaction permit, but for the sake of the question, I am asking)

Okay, I've lost the thread in this discussion. It's hard for me to keep up with the other discussions here. I'll summarize briefly:

The question of market price is discussed mainly in relation to fraud laws. There it's pretty clear that almost no product today has a market price. Regarding interest, the matter is more delicate, since if you have a price, even if it's not a market price, when you charge a higher price for delaying payment or a lower price for advancing it, you may run into interest problems.
I can't remember what the original problem was here. It is permissible to set a different price for late or early payment if you don't have a clear price of your own and there is no market price. If you have a clear price and you change it, it may be prohibited.
As for the transaction you described here, I'm not sure that the rest of the transaction is relevant here. You're not talking about a loan, but about a consignment for sale. This is exactly the definition of a transaction, since the money or goods belong to the consignor and are given to you, half as a loan and half as a deposit, and then the giver's profit is on half of the deposit. But with you, you are not making a deal for the shipper, but are sent to sell certain goods for him at a certain price. The discussion is not about how you will transfer profit to him, but how much you will pay him if you return the goods to him.