Musannaf Ibn Abi Shayba 7:229

Ghundar narrated to us, from Shu'bah, from al-Hakam, from 'Abd al-Hamid ibn 'Abd al-Rahman, from Miqsam, from Ibn 'Abbas (may Allah be pleased with them both), from the Prophet (peace and blessings of Allah be upon him), who said: "He should give in charity a dinar or half a dinar."