Singapore Airlines via DealBase offers select Singapore Airlines Roundtrip Flights to Asia and Europe with prices starting from $640.90. (On the DealBase landing page, click on "singaporeair.com" in the top line to see this offer.) That's the lowest price we could find for select routes by at least $317, although we saw these fares for a buck less two weeks ago. This price is valid on flights departing on May 15 from Houston, TX, (IAH) with arrival in Oslo, Norway, (OSL) with return on May 30. This sale includes flights to Tokyo, Japan, (NRT); Seoul, South Korea, (ICN); Milan, Italy, (MXP); Manchester, England, (MAN); and more. Book this travel deal by March 31 for travel through November 30.

All prices, dates, and booking details were valid at the time of publication.