Sayyiduna Abdullah bin Umar (may Allah be pleased with them both) says that the Messenger of Allah (peace and blessings be upon him) said: "Marry off your women." The Companions (may Allah be pleased with them) said: O Messenger of Allah (peace and blessings be upon him)! For how much dowry? He said: "Whatever their families agree upon."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الصداق / 14378