As discussed previously, there are two categories of IP addresses:
Public Public addresses are assigned by Network Solutions (formerly this was Inter-NIC) and can be purchased as well from IANA. Most organizations don't need to purchase their IP addresses directly, however. Instead, they get the IP addresses they need from their Internet service provider (ISP).
Private Private addresses are reserved for Class A, B, and C networks and can be used without specific assignment. Most organizations follow the private addressing scheme as determined by their information technology (IT) department, and in which case, they would request IP addresses from the IT department.
Technically, if your organization doesn't plan to ...