This post is also available in: Nederlands (Dutch)
We advise everyone to buy and sell tickets only through reliable and verified points of sale, such as Ticketswap. If you only want to sell 1 ticket out of 4 tickets. Then try the PDF Splitter. If you type this in on Google you can separate your tickets.
You can also sell your bus combination tickets, even if it indicates a price of € 0.00.
Unfortunately you cannot sell a promo ticket.