Murabahah means that the seller sells something while making clear: This cost me so much, and now I am selling it at such-and-such a price with this much profit.
Muhammad (may Allah have mercy on him) says that whenever Sayyiduna Uthman bin Affan (may Allah be pleased with him) bought a caravan of camels, he would say: Who will give me a profit of one dinar on this rope?
Hadith Referenceالسنن الكبرى للبيهقي / كتاب البيوع / 10793