I've been twice. I think tickets cost about $150. For me with flight and hotel, that usually tacks on another $1500. It's generally a $2000-$2500 event with food and Disney and stuff (Canadian currency).
There's a huge room with activities, games, booths to buy merch from various YouTube channels. There are challenges you can join in. Last year there were a few stages with various YouTubers doing Q&A's. Outside that room, there are smaller rooms where you can go to learn different things (this is where the conference part comes in)
For the community pass, this generally involves a smaller setting where you can listen to YouTubers discuss their experiences on YouTube and they stick around to answer a few questions. If you get the creator pass, you go upstairs. There are rooms to chill out in, demos from different companies (last year Adobe and Panasonic were set up discussing their products). There are even smaller presentations that are more based on becoming a YouTuber, stats, how-to build your channel, legalities, etc).
If you get the industry pass, you go to the uppermost floor where there are presentations based more on the industry (I've never gotten the industry pass, but from the titles of the presentations it seems like more business-based conferences).
Outside there are different performances going on and an area full of food trucks. At the end of each day, a concert is held in the larger stage area. Usually George Watsky and the Gregory Brothers are the main performances and they bring in other YouTubers (musical) to perform. I didn't know many of the performers last year, but the previous year I went, Chester See and Meaghan Tonjes performed.
This year, VidCon is extending to the hotel to add more presentations. It's getting to be a very, very big event. Well worth going. There's always so much to see and do.
When I go, I usually spend a few hours in the main area, checking out the booths and the Q&A's. I tried to go to as many presentations as I can. I'm not the most outgoing person, but I'd like to try to meet more people this year. I think a lot of people tend to network and promote their channels, which is probably what I should be doing.
Have fun if you go! It's a great experience (I hope this was somewhat helpful)