Musannaf Ibn Abi Shayba 8:139

Abu Bakr narrated to us, he said: Yahya bin Salim al-Ta’ifi narrated to us, from Hisham bin Urwah, from his father, and from Ubaydullah, from Nafi, from Ibn Umar, he said: "‘Whatever is available of the sacrificial animal’ (fama istaysara min al-hady) is between the cheap and the expensive."