SAS has round-trip flights from Los Angeles (LAX) to Hamburg, Dusseldorf, Oslo, Copenhagen, Stockholm, or Helsinki (HAM, DUS, OSL, CPH, ARN, HEL) for $324-$348. Flights January to May.
Note: Carry on bag with a maximum weight of 18 lbs is allowed for free on SAS. You can avoid seat selection fees by accepting the randomly assigned seat at the gate.
Note: Other destinations in Europe are also “on sale” but most of those have long connection times or crappy routing.