On a side note, why would you buy a one-way ticket? Every time I've ever checked it's cheaper to buy a two-way ticket and then just not use the return flight.
That has not been my experience at all. I just checked a flight from Gothenburg to Amsterdam leaving in three weeks time(a random example), and a one-way ticket was almost exactly half the price of a return flight. In fact it's been a long time since I've seen too significant a discount for a return flight vs two single flights.