I may be biased but SW can be VERY cheap. They don't really change thier rates as the time of travel goes on so you can really hold out for that special offer.
Also, you get TWO checked bags for free and like all airlines two carry-ons. That's quite a bit of luggage. I haven't flown that many airlines recently only SW and Frontier. But on SW you get free drinks (has to be soda/lemonade/ water etc) and snacks. Pretzels or peanuts. Most people don't know this but you can have refills and extra snacks for free if you just ask.
Also, I know this is the "Family" section but alot of FF sell thier comped drink tickets online. Check ebay for "Southwest Drink Tickets". If you're not traveling with kids and you're only using disney busses for transportation I don't see why you cant have a cocktail on your ride. I actually had no idea that this happened untill a read this book about disney.