During the Dediqated Sale, you will be able to buy 4 tickets per order. You can purchase 9 tickets per order during the General Sale.
Exception to the above is when you buy tickets in combination with a Travel & Stay package. The maximum amount of tickets you can buy with a Travel & Stay package is the maximum amount of occupants of your purchased accommodation. For example, if you purchase a 20 person Friends Camp, you can also purchase 20 tickets.