Toll-free numbers besides 844 include 800, 888, 877, 866 and 855. The number 800 was the original toll-free number, and it is still in use today.
Toll-free numbers are issued to businesses or individuals on a first-come, first-served basis and allow people to call these numbers at no charge. They are used by many different types of businesses and are most often linked to telemarketing and customer service.
It is important to note that these prefixes are not interchangeable; two numbers that are identical except for the prefix will not route the calls to the same place.
Toll-free numbers are loosely regulated by the Federal Communications Commission, or FCC, but assigned by different organizations. The FCC's primary role is to keep businesses from hoarding toll-free numbers. The organization also makes sure toll-free numbers are easily moved from one service provider to another.
Businesses pay a premium for toll-free numbers so their customers can contact them at any time, for free. They obtain these numbers by contacting one of hundreds of responsible organizations set up to handle such requests. Often, toll-free numbers can be reserved and some companies recommend reserving all possible misdial combinations in attempt to keep customer frustration low when they call the wrong number.