Sayyiduna Abu Sa'id (may Allah be pleased with him) says that in the time of the Messenger of Allah (peace and blessings be upon him) we used to give, as Sadaqat al-Fitr, one sa' of wheat, barley or cheese (aqit).
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الزكاة / 7729
Abu Hudhayfah (may Allah have mercy on him) says that Sufyan (may Allah have mercy on him) narrated the hadith with the same chain, saying: "In the time of the Messenger of Allah (peace and blessings be upon him) we used to give one sa' of wheat, dates, barley, raisins or cheese (aqit)." When Amir Mu'awiyah (may Allah be pleased with him) came and the brown Syrian wheat (samra') arrived, the people considered it equal to two mudd of wheat.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الزكاة / 7730
Sayyiduna Abu Sa'id al-Khudri (may Allah be pleased with him) says that some Bedouins came to the Messenger of Allah (peace and blessings be upon him) and said: O Messenger of Allah! We are owners of livestock; will Sadaqat al-Fitr be waived for us? He (peace and blessings be upon him) said: "No. Pay it on behalf of every young and old, male and female, slave and free person: one sa' of dates, raisins, barley or cheese (aqit)."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الزكاة / 7731
Hushaym narrates from Abu Hurrah that al-Hasan (may Allah have mercy on him) was asked about the Bedouins: what should they pay as Sadaqat al-Fitr? He said: Let them pay one sa' of milk.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الزكاة / 7732