Tickets are paid for online using a credit card, and once payment has been accepted you will be able to print out your tickets (the tickets can be printed in color or black and white, either are valid). There is a unique barcode at the bottom of each ticket which will be scanned at the entrance with a special machine that checks the validity of the ticket, just like the barcodes on boarding passes which are scanned at the airport. If you are unable to print your tickets, it is possible to present the barcode on the screen of your smartphone at the event entrance. You can print out as many copies of your ticket as you like, but each ticket/unique barcode can only be used once to enter the event. After your unique barcode has been scanned and validated, and you have been granted entry to the event, your entry will be recorded by the system and your unique barcode becomes invalid, so another person cannot re use your ticket to gain entry. The website which handles and processes our online ticket sales does charge a small commission (usually varying between 1.99 and 2.99 euros per ticket).