What is a 1-800 Number? A 1-800 phone number is a toll free number used by both large and small businesses. Toll free 1800 numbers are globally recognized as business phone numbers. This recognition provides a sense of credibility associated with using a toll free telephone number as your main business phone number. Even home-based business owners and solo entrepreneurs who run their business from their cellular phones often use a toll free 1 800 phone number to give their small business a big business appeal.