Muwatta Malik

Yahya related to me from Malik that Muhammad ibn Abdullah ibn Abi Maryam asked Said ibn al-Musayyab's advice. ""I am a man who buys food with receipts from al-Jar. Perhaps I will buy something for a dinar and half a dirham, and will be given food for a half."" Said said, ""No. You give a dirham, and take the rest in food."" (A half dirham did not exist as a coin)