AirBerlin, a OneWorld member, is offering a $499 roundtrip to several European destinations at cut-rate prices from now to Tuesday, with flights from Jan. 12 to Mar. 22. The $499 rate is for Berlin from Chicago, and Stockholm or Copenhagen from NYC. Other city combos, including flights from Miami, are $100 to $200 more, but still cheap. Details at airberlin.com; chart below.