You get what you pay for. The base fare is very cheap, but they make their money off of whatever extra "services" you add on that normal airlines throw in for free. For instance, there are extra fees for picking your seat, carrying on a bag, and drinks (Even water). If you are traveling light or if you are traveling with someone else and can share a checked in bag with them this can be a economical choice.
Be aware that service will be equally as discounted, and your flight may be delayed for more than an hour. I was going to give them a higher rating but after a perfunctory announcement with no other updates about our 1.5 hour delayed flight, and then an announcement that they needed to change a tire once we were all seated, making it a 3+ hour delayed flight, they've been downgraded.