If you acquire 110,000 Rapid Rewards points (Southwest Airlines version of frequent-flyer miles) in a calendar year, SWA will automatically send you a free Companion Pass good for the current and following year. So, if you get a pass now it will be good until Dec. 31, 2017.
A Companion Pass entitles your designated companion to travel with you for just $5.60.
Chase is currently offering 3 different SWA credit cards, and each one has a signup bonus of 50,000 Rapid Rewards points.
See http://www.doctorofcredit.com/chase-southwest-personal-business-premier-cards-both-50000-points/
and http://dealswelike.boardingarea.com/2016/01/11/get-southwest-companion-pass-now/