Abu al-Ash'ath al-San'ani (may Allah have mercy on him) was present at the sermon of Sayyiduna Ubadah (may Allah be pleased with him); (he said:) I heard him narrating from the Prophet (peace and blessings be upon him): "Gold for gold, its bullion and its coin, with equal weight; silver for silver, its bullion and its coin, with equal weight; and wheat for wheat, barley for barley, dates for dates and salt for salt, with equal weight. Whoever gives more or demands more has taken usury (riba). There is no harm in selling barley for wheat hand to hand in cash, with the barley being more."
This is the correct version; the established hadith is authentic from Abu Qilabah, from Abu al-Ash'ath, from Ubadah, as a marfu' (Prophetic) report.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب البيوع / 10479