Cheap flights from Washington DC to Juneau, Alaska for only $219 roundtrip with Alaska Airlines. Also works in reverse.
EXPIREDPROMO: Alaska Airlines Buy One Get One Free (e.g. New York to Portland, OR for only $112 roundtrip)
Alaska Airlines are running a promotion where you can buy one coach class ticket and get another for just the taxes and fees.
Summer flights from Los Angeles to Juneau, Alaska for only $225 roundtrip with Delta. Also works in reverse.