Musannaf Ibn Abi Shayba 35:125

Waki’ narrated to us, from Sufyan, from ‘Umayr al-Khath’ami, from ‘Abd al-Malik ibn al-Mughirah al-Ta’ifi, from Ibn al-Baylamani, who said: The Prophet (peace and blessings of Allah be upon him) said: "And give the women their bridal gifts (sadaqat) as a free gift." He said: They said, "O Messenger of Allah, so what are the 'ala'iq (ties/dower) between them?" He said: "What their families agree upon." And he mentioned that Abu Hanifah said: "He shall not marry her for less than ten dirhams."