Frontier/ Southwest Sales...

Frontier Airlines is having another $19 sale.
From Denver, the $19 fares are being offered to Austin, Dallas, Houston (Intercontinental), Indianapolis, Milwaukee, Minneapolis, Oklahoma City and St Louis. Frontier is also offering $29 fares to Portland, San Francisco and Seattle.
However, those fares are just one-way. The return fares are more expensive and the fares do not include checked bags, carry-on bags, seat assignments and on-board drinks.
Also, the fares are only good on select flights between Feb. 1 and Feb. 12. That's next week! That's not much notice for taking a trip or taking your family on vacation.
So, is it worth it? Let's look at the prices.
From Denver to Austin, the $19 fare is only available on Feb. 6, 11 and 12. The cheapest return fare is $72. Leaving on Friday, February 6 for a weekend and returning on Sunday is $92, Monday $82. Going with the Monday date, that's $101 for the fare. Then add another $15-$20 each way for a checked bag or $25-$30 each way for a carry-on bag. Add another $3 for a seat assignment, each way. That makes the fare, with a checked bag and a seat assignment, at least $137 roundtrip.

Southwest Airlines cheapest roundtrip flight that day, including two bags, is $463.
Let's look at the $29 sale to Seattle. The $29 fares are only available on four days -- Feb. 4, 9, 10 and 11. The cheapest return fare is $72, but those really aren't available near the $29 dates. So, leaving Feb. 11 for a long weekend in Seattle, and returning on Sunday, February 15 is $151. Again, you have to add $15-$20 each way for a checked bag or $25-$30 each way for a carry-on bag. Add another $3 for a seat assignment, each way. That makes the fare, with a checked bag and a seat assignment, at least $187 roundtrip.
Southwest's cheapest roundtrip fare that weekend is $288.
So, if you need/want to go to one of the cities and you can go in the next two weeks, it's a pretty good price. If you can't travel in the next two weeks, this sale doesn't help you.
See the details on the Frontier Airlines one day sale here.
Southwest sale
Southwest Airlines is also having a sale. The best sales are to Austin ($78 one-way), Oklahoma City and Salt Lake City ($90 one-way), Las Vegas ($92 one-way) and Phoenix ($89 one-way). Learn more on Southwest's website. That sale ends Feb. 5.