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?
1. Download the VMware Hypervisor from this page (you’ll need to create an account if you don’t have one – it’s free). For esxi 5 use this page.
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: