If you accept the offer, you'll get the money (less than a thousand); if you refuse, you'll get nothing. As far as I understand, there are no other consequences (yet).
If you refuse the helleborine guys end up hating you and in general any guy associated with that dorm will snub you around campus if you run into them by chance. You also get an event where the rich kid has some guys try to force you to swallow some load which you can avoid if your physicality stat is high enough