One-way airfare vs return tickets
Why does a one-way ticket on most airlines cost almost as much as a return fare?
With very few exceptions, air travellers plan to return to their point of origin and most airlines will want to make sure you're sitting in one of their seats for both legs of your journey.
While major carriers discount the price of return airfares, one-way fares are charged at full price. This sometimes creates the anomalous situation whereby a heavily discounted return ticket will cost less than a one-way fare.
However if airlines started offering one-way tickets at around half the price of their discounted return fare, passengers would shop around for whichever carrier offers the best deal on each sector, and no airline wants to engage in a sector-by-sector price war.
The exception is discount carriers, which do charge around half-price for a one-way fare. Lean and - sometimes - mean, discount carriers know that you're only flying with them because they offer the cheapest price.
Their fares are calculated per sector, regardless of how many sectors you fly with them.
Another option is to pay for a one-way ticket using frequent flyer or reward points, since a one-way ticket costs closer to half the number of points required for a return fare.