VMware indeed introduced such a limitation some time ago, but removed it again after customer many complaints.
The free edition is currently only limited with a restricted API, a 8 vCPU per VM maximum, and it can't be managed by vCenter Server.
As mentioned before, ESXi needs some memory itself for it's operating system, and management, so depending on the VMs you want to run on the host, you may add additional physical memory.
André