If you want to earn big rewards, then you should be ready “to work hard”. The thing is, credit card issuers often offer bigger rewards in rotating categories that change every quarter. So, first of all you should be ready to sign up for each rotating category once it starts. And the second, you should be able to plan your purchases beforehand to grab maximum rewards. If you are ready, then you can apply for one of the Discover it credit cards. Discover offer 5% cash back in rotating categories. Also, you can log onto Discover Deals and earn up to 20% cash back on deals from major merchants.