It is narrated from Sayyiduna Ibn Abbas (may Allah be pleased with them both) that the Messenger of Allah (peace and blessings be upon him) said: "Marry off the unmarried women" he said it three times "for whatever (dowry) the families agree upon, even if it is a handful of arak (twigs)."
Hadith Referenceالمعجم الكبير للطبراني / باب العين / 12934