Question 9: Is the groom responsible for meeting all the marriage requirements alone? Is the bride’s family allowed to impose conditions concerning these requirements?
Answer: The basic ruling is that it is obligatory upon the groom to pay Mahr (mandatory gift to a bride from her groom) to the bride. They should mutually agree to state its amount. If any excess is needed, it should be settled according to mutual agreement. It is noteworthy that the agreement should conform to the purified Shar` (Law) as the Prophet (peace be upon him) said... read more here.