Numerous enterprise-grade features are beyond the scope of a free VMware virtualization setup, but the cost savings might offset this loss of functionality.
Ask the average small business IT director how much VMware costs and the answer is likely to be too much. A free hypervisor like vSphere Hypervisor doesn't completely eliminate the cost of VMware virtualization. Fleshing out the virtual data center requires reporting, capacity monitoring and backup tools. You can enlist free third-party tools, if you're satisfied with what features are available and the limitations.
Many free virtualization tools are demoware with limited functionality or trial periods. Some, like those covered in this project, are 100% free for unlimited business use, and a combination of these products will create a viable virtualization infrastructure for small and medium-sized businesses.