Cardholders of the Delta SkyMiles American Express card can earn 100 percent bonus miles when purchasing miles and paying with a SkyMiles American Express. Plus, you’ll earn double miles on the purchase itself for charging the miles to your card. For example, if you spend $120.40 (including tax) to buy 4,000 miles, you’ll receive a total of 10,240 miles for your purchase. Visit http://insideflyerus.wpengine.com/link/?2521 to log in to your account and buy miles.