All perfect praise be to Allaah, the Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad, sallallaahu ‘alayhi wa sallam, is His Slave and Messenger.
Slaughtering a sacrificial animal (on ‘Eed Al-Adh’aa) is a confirmed act of Sunnah, and some scholars even considered it obligatory. Slaughtering a sacrificial animal is superior to giving its price in charity. Shaykhul-Islam Ibn Taymiyyah said, “Slaughtering a sacrificial animal [on ‘Eed Al-Adh’haa] is superior to giving its price in charity, so if a Muslim has money that he wants to use as a means of drawing nearer to Allaah, then he should slaughter a sacrificial animal [on ‘Eed Al-Adh-ha].” Therefore, it is permissible to spend the amount of money which you save from your salary for the purpose of charity on buying a sacrificial animal (on ‘Eed Al-Adh’aa), rather, this is preferable, if Allaah wills.
Allaah Knows best.