In general, phone numbers are not free. Phone numbers are controlled by various phone companies. To have a phone number assigned to you, someone must pay for phone service. To call any phone number, an active phone service must be in use.
Phone numbers can be assigned to land line phones or cellphones. Some telephone providers are AT&T, Sprint and Verizon. The costs vary depending on the service required. If calling on a land line to a phone number out of the area in which the service is located, it may be considered long distance, and extra charges may be added in addition to the base cost of the plan. Government-assisted phone plans are available to those who qualify, but they are not necessarily "free," as the cost is deferred to public funding.