With your credit card terminal, you will need a receipt printer to issue receipts and slips for customer signatures. Whether your receipt printer is built in to the terminal or a stand-alone unit, you will need to choose between the two main types of printers: dot matrix and thermal. You should choose credit card terminals based on price, speed, and reliability.
Dot matrix receipt printers, also known as impact printers, use pins and an ink ribbon to print on regular paper. Dot matrix printers are fairly inexpensive, usually $200 - $400. Print speeds tend to be low, in the range of 1 to 4 lines per second.
Thermal receipt printers use heat and special heat-sensitive paper to generate receipts. They are slightly more expensive, ranging from $300 to $500, but they are faster, quieter, and generally more reliable because they have fewer moving parts. They can be much faster than dot matrix printers, with speeds of 10 to 15 lines per second.
A third type, inkjet printers, is fairly rare. Their only real advantage is the ability to print in multiple colors; they have neither the speed of thermal printers nor the low costs of dot matrix printers.
Over several years of use, the higher costs for thermal paper are just about balanced out by the need to buy both paper and ribbons for dot matrix printers. Changing paper can be a hassle if there are customers waiting - many printers now have "drop-in" paper loading which simplifies the process.