Where I'm actually living, during one of my too often trip I had the opportunity to look at an advertise, which explained a bit how is determined the price of a plane-ticket. You'll be surprised to learn than more of the half is only taxes (either from departure airport/country or from destination airport/country). So for the question, as far as the strictly speaking cost of the plane is the same, their shouldn't be any difference. By saying this, their could be in fact a difference: taxes from the departure airport of your travel when you're buying a go and back plane ticket. I saw cases, when you go back first (not a mistake), taxes are less on the overall flight and the overall plane ticket is less expensive ; but local regulations don't allow you very often to do such a trip ;) Regards, Eric