The Citi - Shell Gas MasterCard is an excellent way to earn cash back on your gas purchases. My husband and I both have this credit card and use it each time we purchase gas at Shell. I love that there is a tiered rewards program for a credit back on your purchases depending on number of gallons of gas you purchase in a billing cycle. We typically earn $0.10 back per gallon of gas purchase but have earned $0.15 or even $0.20 back on gallon of gas purchased. This credit card is an excellent way to track the number of gallons of gas we use each month and it is an excellent way to earn a little bit of money back on our gas purchases. It is not a lot of money that we get back each month but the savings do add up over time. Overall, I am very happy with the features of this credit card and plan to continue to use it. Customer Service I have had a couple of minor issues with this card working at the gas pump and the customer service representatives have always been extremely helpful and help resolve the problem in a timely fashion.