Love Those Fuel Loyalty Cards and CC Cash Back

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Companies don't create these "gifts" because they are nice guys. They do it because there is some catch, where a consumer who does not read the fine print ends up paying more than the gift is worth.
Airline credit cards with high interest rates and annual fees are a good example, so are most "big bank" cash back credit cards. If you don't pay these cards off in full every month and cancel them before the annual fees kick in, you are probably losing money.