A good resource is the main website,
www.halloweenhorrornights.com.
As for prices, it runs $20-$25 with an AP, multiday, or same day ticket.
HHN event only tickets run around $50. A good strategy is to be in the park before 5:30. If you do this, you can linger around the parks until the haunted mazes open. You can get first dibs on the mazes and go through them with a little wait.