I bought a return ticket in Dublin for Cork express, paid cash in Dublin, no problem boarding in Dublin but the return leg I was told wait it's online bookings first, and if there was a seat available after all online bookings then I could board, I was a little nervous I'd miss my flight from Dublin luckily there was a seat available. I'd advise anyone don't pay cash for tickets at least not return tickets, book online your seat is guaranteed then. Aircoach don't tell you this just happy to take your money. They should explain the risk of paying cash for return ticket ie that your return seat is not guaranteed.