RSVPify - A powerful and awesomely customizable platform for selling tickets online for your event.
PurpleTrail - Whether it is about birthday or wedding party or holidays, you just need to name the event and PurpleTrail will provide you the apt invitation solutions.
Whoozin.com - Free RSVP Online | Track RSVP’s and Sell Tickets for your events and recurring meetings.
Celebrations.com - Find cool, unique, artist-designed online Invitations, eCards, Party Ideas, Party Planning Tips...
JustRSVP.me - Online Invitations and response tracking for weddings, baby showers, birthdays, parties, and other...
Eventbrite - Discover Great Events or Create Your Own & Sell Tickets