The fair is low, so maybe you'll try it. You can deal with paying for everything except a computer bag. What you can't deal with is the high possibility of not leaving the airport. My recent flight was at 7am. Surprisingly, Frontier was unaware that the evening flight from PHX to ORD (chicago) did not take place so there was not a plane for us to fly ORD to PHX. I got through security at 620 ready to board. There was no agent at the counter. The screens were not on either. I check the status online and it's a go. Check at 630, 30 minutes to departure and we've been delayed 3 hours. Then the attendant shows and says we don't know what's going on and walks away. Customer Service via phone has a wait of 27 minutes. Frontier does not partner with any other airlines, so you have to wait them out.
If you want to travel cheap fly these guys or Greyhound; you'll get there at the same time.