RetailMeNot.com keeps a running list of Southwest Airlines promo codes, coupons and sales. Each code has a success rate and comments that help users determine if the code suits their needs.
Southwest.com offers promo codes directly to the consumer through its Special Offers page, which promotes its current sales and encourages users to sign up for an email list. The company sends out occasional emails highlighting special airfare rates and discounts to those on the list.
SouthwestVacations.com is another means of finding promotions and deals. Often these deals include discounted airfare from Southwest and special rates on hotel rooms when purchased as a package.