It is narrated from Ibn Qusayt (may Allah have mercy on him) that a man was given the good news of a girl, and another man said: Gift her to me. He said: She is yours. Sa'id bin al-Musayyib (may Allah have mercy on him) was asked about this, and he said: Gifting (a woman in marriage) is not permissible for anyone after the Messenger of Allah (peace and blessings be upon him); and if he gives her even a whip as her dowry (mahr), she is lawful for him.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب النكاح / 13357