Creating events is free for all users, if you sell tickets to your events for a price then you have to pay $1/ticket. The $1 pricing is same for whatever price you fix for your event tickets.
Eventzi gives you a custom page for your event, you can add a picture or logo to enhance the event page. If you are selling tickets for your event you can setup the price, discounts, no of tickets you are selling, dates etc. The payments are processed through Paypal, so you may have to pay a small paypal fee accordingly.
You can add guest list as emails, or upload a CSV/txt file. Setup the RSVP options, add some text on the web page and you are done with your custom event page.
Eventzi is a simple and effectinve way for creating events online with RSVP and ticketing options.