Gay marriage is not yet an acceptable form of marriage in our community, but if it were...
... I imagine the bride price would have to be paid by which ever clan the couple goes to become a part of.
It is true that even in heterosexual marriages, a price can be paid where the groom goes to become a part of the bride's family. This is not unheard of.
Similarly, if the couple can decide between the two of them, which clan they will be more a part of, then that will answer the question of who needs to pay. It really doesn't even have to be a matter of which clan they will spend more time with, or stuff like that, but more a matter of responsibiliti es. For example, which clan will handle responsibiliti es when one of their kids get married, or which clan will handle responsibiliti es when one of them dies. That kind of stuff needs to be hashed out and agreed on, otherwise, it isn't a marriage.