Spirit's surprisingly low fare sale invites members of its club to take advantage of round-trip flights from $2. Domestic destinations include Atlantic City, Boston, and Ft. Lauderdale; or visit international cities such as Nassau or Santiago.
Lufthansa's latest Europe sale includes destinations such as Berlin, Geneva, Oslo, Rome, and other European gems. Departures are available from 11 U.S. cities. Competition comes from Air France, American, Continental, Delta, Iberia, and US Airways.
Qantas' Australia and New Zealand sales feature flights to Brisbane, Melbourne, Sydney, and Auckland from both coasts and cities in between. Also look to Delta, United, and V Australia for competing rates.