From Sahih Bukhari (Hadith 2216):
Narrated `Abdur-Rahman bin Abu Bakr:We were with the Prophet (ﷺ) when a tall pagan with long matted unkempt hair came driving his sheep. The Prophet (ﷺ) asked him, "Are those sheep for sale or for gifts?" The pagan replied, "They are for sale." The Prophet (ﷺ) bought one sheep from him
Reference: Bukhari 2216