It is narrated from Sayyiduna Sahl bin Sa'd (may Allah be pleased with him) that the Prophet (peace and blessings be upon him) said: "Give them something in return, even if it is only (the worth of) a whip," meaning in the dowry (mahr) of marriage.
Hadith Referenceالمعجم الكبير للطبراني / باب السين / 5910