Southwest's cancellation policy is so good, it's hard to believe!
Not only can YOU use the funds for anywhere Southwest flies for a year, you can transfer them to someone else, or even sell them on eBay. You can also combine funds from several cheap tickets to buy one expensive one, or use funds from one expensive ticket to buy several cheap ones.
Basically, Southwest won't give a cash refund on "nonrefundable" tickets, probably because it would complicate their accounting too much. But, they do give a full credit usable just about any way you want.