Musannaf Ibn Abi Shayba 13:936

Abu Bakr narrated to us, he said: Abu Dawud narrated to us, from Abu Hurrah, from al-Hasan, that he used to see no harm in buying from a Bedouin for a Bedouin. He said: So it was said to him, "And does he buy from him for a Muhajir (emigrant)?" He said: "No."