If you're a Southwest Airlines frequent flyer, the Southwest Rapid Rewards® Priority Credit Card (see rates and fees) may just be the perfect airline card for your wallet. The card offers perks like a Preferred seat at booking (when available), your first checked bag free and 7,500 bonus Southwest Rapid Rewards points every cardholder anniversary.If you're able to maximize all its perks, it's easy to get outsize value out of the Southwest Priori…