There's going to be one in Florida in May. One coming up in a week in CA (and I expect lots of pictures from Karen.. I wonder if Beat is going??). The convention is in San Francisco in July. I'm not sure about the other dates but the show season is just starting off so there's going to be lots of them as summer rolls on.
The unfortunate part is unless your close to a show your either in for a really long drive or your just outta luck. I'm driving 2 hours, renting a hotel room for a night and driving 2 hours back all for the First Coast Bettas show.
It depends on the club as to when the public is allowed in. My clubs one show had what's called "open judging' where you can be in the room while the fish are judged. Some clubs have "closed judging' where only the judge, apprentices, and someone else (brain fart) are allowed in the room.
Usually there is a viewing time and then there is the auction that is open to the public too.
I've never heard of them charging tickets. Lets be honest what regular joe is going to pay to come in to look at fish? Having a well publicized, free show is a great way of bringing people into the hobby.