There are several factors to consider when setting up a credit card processing system for a new retail or internet business. The first step is to set up a merchant account via a merchant account service. Such services act as intermediaries between you and the credit card companies. If you are a retail business, you will need to purchase a processing terminal through which credit cards will be physically swiped. Such terminals can cost anywhere from $100-$1000, and can be purchased via merchant account services or else independently. Finally, you will need to be sure that your POS (Point of Sale) system is properly set up to interact with the credit card terminal. User manuals or else your merchant account service can usually help with this.