Hello. Let me start by saying I know next to nothing about how a website is built. I have an idea for a website and I'm trying to find out what all will be involved in the way of time and cost to build what I want.

I need a site that will allow users to submit their contact info regarding upcoming events. Other users would be able to search for those events by state and click on a link that would take them to the stored contact info for events in their state.

Each user would need to create a login for them to be able to access the stored contact info.

I would also like to have the capability for registered users to create their own information page on the site and be able to update information from each event so that others can log in and view the results of the event as updates are posted.

How complex is this? Is this going to cost a lot of money to get in place? If it's affordable, where would I start my search to find someone to build this site?

Is there any chance of generating ad revenue from such a site?

As you can see, I'm clueless. Any insight would be most appreciated.