Just scroll down to the bottom of the page and fill out the black form with your Southwest mileage number to get 500 points for free. Of course you’ll be signing up to get spam from them, so it’s always a good idea to have a dedicated spam email address for offers like these.
“Limited-time offer. 500 Rapid Rewards Points will be applied approximately 8-10 weeks from submission. Offer available once per valid Rapid Rewards account.”