The Citi Double Cash card is a popular choice for Samsung Pay users due to its simple and rewarding cash back structure. With this card, you can earn 2% cash back on all purchases – 1% when you make a purchase and an additional 1% when you pay it off. There are no category restrictions or limits on how much cash back you can earn. The Citi Double Cash card also offers a 0% introductory APR on balance transfers for the first 18 months.