Questions about Warped Tour?

I might be going to Warped Tour this year,and I want to know a few things.How much do the tickets cost?Can I get tickets at the venue/gate or do I have to purchase the tickets online?Do the tickets run out if I purchase them at the venue/gate?Anything else you want to include,feel free to add.I might be going to the one in Pomona or Ventura.