All non-demo RPG games cost €4 to play. You will be able to purchase a ticket for the slot ahead (starting at 10am, 2pm, 6pm, 10pm), unless the next slot would be on the next day (e.g. you can’t book Saturday morning games on Friday night).
The only exception to this is Pathfinder: You can book any slot for the weekend using Warhorn (but you must also pay for the slot at front desk, after the Con opens.)

No online RPG ticket sales are available. This system is designed to reduce disappointment due to no-shows making games non-viable.