Frontier, Southwest and United all having the same sale price.
Here are UA valid LGA-DEN dates:
October 16,17,18,19,20,23,24,25,26,27,30,31
November 7,13,14
And for DEN-LGA on UA:
October 16,17,20,22,23,24,25,26,27,30,31
November 13
Southwest and United are matching Frontier here. Frontier last day for DEN is 11-14 for the season. Prices therefore pick up after this date.
Great price for Denver.