Muwatta Imam Malik Book of Business Transactions, Hadith 77

Yahya related to me, that Malik said, "The generally agreed on way of doing things among us about a man buying cloth in one city, and then taking it to another city to sell as a murabaha, is that he is not reckoned to have the wage of an agent, or any allowance for ironing, folding, straightening, expenses, or the rent of a house. As for the cost of transporting the drapery, it is included in the basic price, and no share of the profit is allocated to it unless the agent tells all of that to the investor. If they agree to share the profits accordingly after knowledge of it, there is no harm in that."
Malik said, "As for bleaching, tailoring, dyeing, and such things, they are treated in the same way as drapery. The profit is reckoned in them as it is reckoned in drapery goods. So if he sells the drapery goods without clarifying the things we named as not getting profit, and if the drapery has already gone, the transport is to be reckoned, but no profit is given. If the drapery goods have not gone the transaction between them is null and void unless they make a new mutual agreement on what is to be permitted between them ."
Malik spoke about an agent who bought goods for gold or silver, and the exchange rate on the day of purchase was ten dirhams to the dinar. He took them to a city to sell murabaha, or sold them where he purchased them according to the exchange rate of the day on which he sold them. If he bought them for dirhams and he sold them for dinars, or he bought them for dinars and he sold them for dirhams, and the goods had not gone then he had a choice. If he wished, he accepted to sell the goods and if he wished, he left them. If the goods had been sold, he had the price for which the salesman bought them, and the salesman was reckoned to have the profit on what they were bought for, over what the investor gained as profit.
Malik said, "If a man sells goods worth one hundred dinars for one hundred and ten, and he hears after that they are worth ninety dinars, and the goods have gone, the seller has a choice. If he likes, he has the price of the goods on the day they were taken from him unless the price is more than the price for which he was obliged to sell them in the first place, and he does not have more than that - and it is one hundred and ten dinars. If he likes, it is counted as profit against ninety unless the price his goods reached was less than the value. He is given the choice between what his goods fetch and the capital plus the profit, which is ninety-nine dinars."
Malik said, "If someone sells goods in murabaha and he says, 'It was valued at one hundred dinars to me.' Then he hears later on, that it was worth one hundred and twenty dinars, the customer is given the choice. If he wishes, he gives the salesman the value of the goods on the day he took them, and if he wishes, he gives the price for which he bought them according to the reckoning of what profit he gives him, as far as it goes, unless that is less than the price for which he bought them, for he should not give the owner of the goods a loss from the price for which he bought them because he was satisfied with that. The owner of the goods came to seek extra, so the buyer has no argument against the salesman in that to make a reduction from the first price for which he bought it according to the list of contents."