Sadaqat ul-Fitr is the charity we give towards the end of Ramadan. It was instilled upon us by the Prophet Muhammed (SAW) the same year the Ramadan fast was made obligatory for all Muslims. 

Sadaqat ul-Fitr is a way to atone for mistakes we make over the course of Ramadan so as to make our fast more acceptable to Allah. It is also a means to make people spend for the sake of our Rabb, thereby helping the needy and less privileged obtain basic necessities required to take part in the Eid celebration.

Sadaqat ul-Fitr becomes compulsory upon every Muslim who is alive at dawn of the day of Eid, be it a new baby born before dawn or a person who accepts Islam before the break of dawn. It is advised to have paid your Sadaqat ul-Fitr well in advance of the day of Eid as it needs to be distributed and the recipients would also need time to prepare and utilize the Sadaqat. It is reported that the companions of the Prophet Muhammed (SAW) paid their Sadaqat ul-Fitr days before the Eid day.

We should therefore make an effort to pay on time so as to be amongst those who benefit from their Sadaqat ul-Fitr. 

"Ibn Abbas (RA) narrated: Allah's Messenger (SAW) obligated Sadaqat ul-Fitr for the one who fasts as a means of purifying him from vain talk and immoral deeds, and as a means of feeding the poor. Whoever gives it before the Eid prayer will have it counted as an accepted Sadaqat, and whoever gives it after the prayer will have it counted as a charity among charities." - Abu Dawud

The Prophet Muhammed (SAW) said: "The head of a household must pay the required amount for the other members of the household." - Muslim

"Sadaqat ul-fitr is obligatory on every Muslim at the conclusion of the obligatory Ramadan fast, whether married or single, young or old, male or female, slave or free." - Bukhari

"Ibn Umar (RA) narrated that Allah's Messenger (SAW) would order paying Sadaqat ul-Fitr before going to Salat on the day of Eid ul-Fitr." - Bukhari, Tirmidhi

Narrated Ibn Umar (RA): Allah's Messenger (SAW) has made the payment of Sadaqat ul-Fitr obligatory, either one Sa' of barley or one Sa' of dates (per head) on young and old people and on free men as on slaves." - Bukhari

For further reading on this topic, refer to the follow links: Sadaqat ul-Fitr by @smugdisguise and Sadaqat ul-Fitr.