The esxi (standalone server) is free, but it must be licensed. If not, it installs as 60 days trial, which expires after 2 month.
How-to receive and apply VMware Free License to VMware ESXi 6.0?
After that you can login to your newly created account at VMware. Once logged in you should see this page from which you can:
- Copy the license key
- Download the Free VMware Hypervisor
- Download the vSphere client for management
- Download VMware tools for Linux guests (an ISO file)
2. Connect to your ESXi host > Configuration TAB > Licensed features (this is same in ESXi 5.x as well as in ESXi 6.0).
Your license information: