I understand that a Husband must give Mehr before/on marriage.

But is it something that needs to be mutually agreed upon as part of marriage contract as it is done these days or the original intent was that husband should give a gift to his wife that he can afford to give without needing to ask her (or her father/relatives)?

I'm asking this since these days the Mehr is usually demanded by bride's family (eg. 10 tola gold, 1 million cash, etc) and it is quite enough such that it is getting harder for muslims to get married. What is the islamic ruling in this regard?