The official GLPI Network Cloud offers a (usually 1 user or small asset count) without a credit card. You sign up with an email, and they create an instance – still no registration key, just an account login.
For years, FusionInventory was the gold standard for free GLPI automation. While GLPI has shifted toward its native agent, FusionInventory remains a highly capable, community-driven alternative. 100% Free (Open-Source). glpi registration key free