Musnad Ahmad 1153:516

'Affan narrated to us, he said: Hammad ibn Salamah narrated to us, he said: Ibn al-Tufayl ibn Sakhbarah informed me, from al-Qasim ibn Muhammad, from 'Aishah, that the Messenger of Allah, peace and blessings of Allah be upon him, said: "Verily, the greatest of marriages in blessing is the one that is easiest in expense."