I suspect the answer is yes, but I'm looking for confirmation and a quick Google search didn't turn up anything definitive.
I'm flying into London Luton tomorrow morning and want to take a coach to Victoria station. I am unable to buy a ticket online (my bank is being obstinate and not letting the transaction through), so I would like to know if I can buy an easyBus or National Express or Green Line ticket from a kiosk at the airport or the driver him/herself.