Right now you can get the two day 2015 tickets until the 25th of April for $50. here is the link....then they will be $60 until end of august when the second headliner should be getting announced then they will go up again...so get them now while they are this cheap.
http://ragnarokkrmetal.bigcartel.com/product/two-day-festival-ticket
http://ragnarokkrmetal.bigcartel.com/product/two-day-festival-ticket