"I asked 'Aishah about that and she said: 'The Messenger of Allah got married (and married his daughters) for twelve Uqiyah and a Nashsh'" which is five hundred Dirhams.
Sunan an-Nasa'i Book 26, Hadith 152
← Previous Hadith "And if you fear that you shall not be able to deal justly with the orphan girls then marry (other) women of your choice." She said: "O son of my sister, this refers to a female orphan who is in the care of her guardian, and her wealth is joined to his, and he is attracted to her wealth and her beauty. So her guardian wants to marry her without being fair with regard to her dowry, and without giving her what someone else would give her. So they were forbidden to marry them unless they were fair to them and gave them the highest possible dowry that is customarily given, and they were commanded to marry other women of their choice." 'Urwah said: "'Aishah said: 'Then later on, Allah, the Mighty and Sublime, revealed concerning them: 'They ask your legal instruction concerning women, say: Allah instructs you about them, and about what is recited unto you in the Book concerning the orphan girls whom you give not the prescribed portions and yet whom you desire to marry.' 'Aishah said: 'What Allah, Most High, mentioned here that is recited in the Book is the first Verse in which it says: And if you fear that you shall not be able to deal justly with orphan girls then marry (other) women of your choice.' 'Aishah said: 'What is referred to in the other Verse -and yet whom you desire to marry- is the desire of one of you not to marry orphan girl who is under his care if she is lacking in wealth and beauty. So they were forbidden to marry those orphan women to whose wealth they were attracted unless they were fair, because of their desire not to marry (those who were lacking in wealth and beauty.)'"

Sunan an-Nasa'i Book 26, Hadith 151 Next Hadith → "The dowry, when the Messenger of Allah was among us, was ten Awaq."

Sunan an-Nasa'i Book 26, Hadith 153