Musnad Ahmad 33:692

'Affan narrated to us, Abu 'Awanah narrated to us, Abu Bishr Ja'far ibn Abi Wahshiyah narrated to us, from Sulayman ibn Qays, from Jabir ibn 'Abdullah, who said: The Prophet, peace and blessings of Allah be upon him, called Abu Taybah, and he performed cupping on him. He said: Then he asked him, "What is your tax (fee)?" He said: "Three sa's." He said: So he remitted one sa' for him.