Dallas, Texas to Kona, Hawaii. $405 round-trip, including all taxes. 330 day travel period.
For upcoming months this fare is easier to find using the United.com website and then choosing the flexible date search. For travel beyond April, dates can easily be found on Orbitz.
Say "Aloha" to some other great round-trip fares to Hawaii departing from both DFW and MIA to other major Hawaiian airports including: Honolulu (HNL), Maui (OGG), and Kauai (LIH) ranging from $405 to $415.