Cheap flights to Hawaii have become the norm since Southwest began flights to the islands. From time to time, you can find round-trip flights from the West Coast in the mid-$200s. However, the East Coast is frequently left envying their friends on the other side of the country. But be envious no more!
For trips taken in August and September, East Coasters, as well as a few cities in the South and Midwest, can find round-trip flights for $391, as noted by Scott's Cheap Flights. The site additionally highlights that the "normal price" is usually around $800, so this is a damn fine price for anyone looking to spend some time in Hawaii. The low prices aren't part of a specific sale, so the airlines and dates vary (though, the vast majority are through United).
Among the deals are round-trip flights to Honolulu from Austin for $447, Dallas for $463, Indianapolis for $426, Kansas City for $495, Milwaukee for $428, Montreal for $451, Nashville for $431, New Orleans for $453, Oklahoma City for $434, Omaha for $503, Orlando for $391, Ottawa for $430, St. Louis for $430, Tampa for $474, and Toronto for $428. There are also good prices from Milwaukee to Kona ($442) and New Orleans to Kauai ($434).
As you'd find with any flight deal, the prices can change rapidly. If you're looking to take advantage, you should buy soon because options can disappear and prices can rise when fares are this low.