Swiss Airlines has San Francisco to Gothenburg Sweden SFO-GOT on sale again for a few dates in April and May for $617. These fares were prevalent three weeks ago when it was possible to fly in June or August at this price. This fare is only available for some April and May dates today.
This fare is bookable on Swiss Airlines website. I used the Priceline image for its more compact display.
This Swiss Airlines deep discount economy K class fare earns 50% miles in United Mileage Plus for 6,563 redeemable miles.