Sadaqat-Ul-Fitr is a compulsory Zakat o be paid at the end of the month of Ramadan.
Narrated Ibn ‘Umar (may ALLAH be pleased with him): Allah’s Messenger (Peace be upon him) enjoined the payment of one Sa’ (3 kilograms approximately) of dates or one Sa’ of barley as Zakat-ul-Fitr on every Muslim salve or free, male or female, young or old, and he ordered that it be paid before the people went out to offer the ‘Eid prayer.
Narrated Abu Said Al-Khudri (may ALLAH be pleased with him): In the life time of Allah’s Messenger (Peace be upon him), we used to give one Sa’ of food (edible things) as Sadaqat-ul-Fitr (to the poor). Our food used to be either of barley, raisins, ‘Aqit (dried yogurt or cottage cheese) or dates.
Narrated Ibn ‘Umar ( may ALLAH be pleased with him): ALLAH’s Messenger (peace be upon him) has made Sadaqat-ul-Fitr obligatory, either one Sa’ of barley or one Sa’ of dates, enjoined on young and old people, and on free men as well as on slaves.