SAS has round-trip flights from Chicago (ORD) to Paris, Manchester, or Milan (CDG/MAN/MXP) for $442-$459 with a connection. Flights November 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.