When it comes to 3% cash back, there are a few main categories you can choose from. Typically, these include grocery stores, gas stations, restaurants and select department stores. Depending on the card issuer and type of credit card you have, other bonus categories such as travel expenses may also be eligible for 3% cash back rewards. Additionally, some cards offer rotating quarterly bonus categories that allow customers to earn extra points or rewards when they use their card at specific merchants during certain time frames. Finally, many issuers will offer additional reward levels for high-value purchases made in designated spending categories like home improvement stores and online shopping sites.