The Internet Corporation for Assigned Names and Numbers (ICANN) oversees the allocation and management of IP addresses. This entity allocates IP addresses to various entities and organizations, which in turn assign them to end-users. Nonetheless, the original allocators maintain ownership over these addresses.
Given that IP addresses are publicly accessible and do not disclose specific personal details, it is permissible to use an IP lookup service to ascertain someone's IP address.
There is essentially no distinction among these terms. Despite the different nomenclature, they all serve the identical purpose: to identify your IP address and geographical location, and to reveal the Internet Service Provider associated with your IP.
Yes, the IP Address Lookup service is offered free of charge. IP addresses, being publicly accessible, can be freely checked by any internet user at their discretion.