Get 30,000 bonus miles when you sign up for a Gold Delta Skymiles Card and spend $500 within the first three months. That's the most miles we've ever seen for opening this card alone, and among the best bonus offers we've seen at that that low of a spend threshold. Plus, you get free checked bags on all Delta flights and 20% off Delta purchases plus double miles. You'll also get one bonus mile for every dollar spent on select purchases, and more. Plus, there's no annual fee for the first year (a $95 annual fee applies for each additional year, but saving the cost of checked baggage fees more than makes up for it).