If you want a cheap no frills flight use Spirit. I fly it once or twice a month and it's A ok in my book.
For best service use their website. Spirit is very transparent about what it charges extra for. Nothing is free on Spirit but I prefer to keep my $$$.
The seats do not recline which I love. I hate someone pushing into my space. The seats are small so if you are overweight or tall you will be uncomfortable in the regular seats. Upgrade to the seats in the front of the plane and pay more.
If you want a snack be prepared to pay. Water, coffee, tea, or soda costs you a few dollars. Do you want entertainment? Bring your own. Nothing is free on Spirit. But that's how this airline keeps prices low.
The stewards and stewardesses are super nice. Just be aware nothing is free on the flight. You can bring 1 personal item only, the size of a backpack but anything larger you pay for.
If you want cheap, no frill flights Spirit rocks.