As of February 2015, it is free to call an 855 number. The Federal Communications Commission states that 855 is one of the six codes that begin a toll free number. These numbers give consumers the ability to call other parties without being charged for the phone call.
The remaining five toll-free codes are 800, 844, 866, 877 and 888. These numbers are often assigned to businesses that are wanting to market in multiple areas so potential customers can call free of charge. Toll-free number are always assigned to businesses and other organizations on a first come, first serve basis.