The CITGO credit card will be a good option for you if you are going to fill up only at CITGO gas stations. However, you may not want to apply for this card if you have a habit of carrying a balance on your credit cards. The CITGO card comes with 24.99% APR which can eat up rewards you earn if you do not pay off the card balance each month. The 5 cents off per gallon offer is also not the most generous one.
This offer can easily be beaten by a 2% cash back offered on the Discover it® chrome. Earn 2% cash back at gas stations and restaurants on up to $1,000 in combined purchases each quarter. Plus, earn unlimited 1% cash back on all other purchases – automatically. Plus Discover card comes with lower APR and a 14-month interest introductory period (when the introductory interest rate is over, the ongoing APR will apply).
As you see regular rewards credit cards offer bigger rewards and it means you will be able to save more on all your expenses.