Eventbrite.com allows you to set up an event with online registration–perfect for those seeking to fill a class or workshop. It can process credit card payments and put number caps on events, adding and managing a waitlist for any cancellations. From the site, you can print name badges and certificates for the event itself. Eventbrite is free for free events, while those selling tickets will pay 2.5 percent plus $0.99 for each pay ticket sold.