something called "yield management". They do not sell 180 tickest at 2 euros. They may sell a few at that price ( plus all applicable taxes and charges), but as the load factor for a particular flight increases so does the price. By the time the aircraft is nearly full the ticket price may well seem very un-low cost indeed. The yield for a good load factor will be very good. Add to this the revenues generated by sales on board, ancillary charges for administrative changes and operating subsidies from airport operators, transport companies etc , and you can see where a lot of their income comes from.