If you truly need ESXi 5.5 (e.g., for an old CPU without VT-x2), consider using the or buying used hardware that supports newer versions. Avoid “license key” searches—they lead nowhere good.

If you require vMotion, HA (High Availability), or DRS, you need a paid license.

VMware ESXi 5.5 was a cornerstone of the vSphere 5.5 suite. Although it is now considered "End of Life" (EOL), it remains popular for specific use cases: