This tool is completely customizable to meet the exact needs of your event and budget. When your current participants get a designated number of their friends to sign up, give them automatic refunds (partial or full), or custom rewards such as T-Shirts, Hats, Pint Glasses, or no reward at all.

To further incentivize new participants to register, set up the referral codes with discounts for future registrations to make it easier for your participants to market to their friends (i.e. $5 off for anyone registering with a referral code).

Learn more here: http://support.athletereg.com/entries/107606823-Referral-Codes