Norwegian has some low fare dates for travel from Oakland to Stockholm, Sweden as low as $412 round trip for travel in November and December for five or six departure dates, Several more dates are available for under $500 and many more dates in winter 2016 at $442 round trip.
If you can get by packing light with one carry on bag and you don’t mind booking without a paid seat assignment, then you can keep the cost of the flights at that fare.
Norwegian Airlines Oakland OAK – ARN Stockholm
$411.80 November 16–23, 2015
There are a few dates for travel to Oslo as low as $441, and more dates at $552. Copenhagen is currently the higher priced destination for Scandinavia at $599 on some dates.
Los Angeles – Copenhagen $445 to $554 as low fares on Norwegian October to December.
Los Angeles – London LGW $631 for some dates in November and December.
Los Angeles – Stockholm $485 to $555 on a few dates September and October.
Los Angeles – Oslo $441 to $542 for several Thursday departures October and November.