There are a few different things you can get for refferring someone if you are in a State taht can legal accept gifts for real estate referrals (I only know that NY Can and CT Cannot) There is a tiered cash incentive that is starts at $200 for the first referral and I believe maxes out at $500. There are other choices but I don't know what they are.
If you are in CT or another state that cannot accept the gift then they send you a thank you letter and a pin or something.