A toll-free number is a number that is generally associated with a business or individual that can be called without incurring a calling charge. These numbers generally start with certain three-digit codes, such as 800, 877, 866, 855 or 844.
Charges that are incurred during a call to a toll-free number are charged to the party that the number belongs to. These numbers are generally used in business for the purpose of either customer service or telemarketing. Toll-free numbers are assigned on a first-come, first-serve request basis by organizations that are granted access to the SMS/800 database and are considered by the FCC as "Responsible Organizations."