Musannaf Ibn Abi Shayba 13:243

Mu'tamir ibn Sulayman narrated to us, from al-Akhdar ibn 'Ajlan, from Abu Bakr al-Hanafi, from Anas ibn Malik, from a man of the Ansar, that the Messenger of Allah (may Allah bless him and grant him peace) sold a saddle blanket and a drinking cup to the highest bidder.