1. Event add-ons are specifically designed for purchases that do not include admission to the event.

2. Add-ons can be things that are purchased without a ticket purchase or only after a ticket level purchase has been selected by setting Require Level Purchase for Add-on Selection to YES on the Event Settings tab.

3. Add-ons are generally things like traditional paper raffles, t-shirts, advertising, and sponsorships that do not include tickets or admission to your event.

4. You can also create event levels with zero attendees per purchase if you wish to use coupons for the items. 

5. Add-ons and event levels with zero attendees will not appear on the Event Attendance grid, only the Events and Gifts grid will include the transactions.