License price per vCenter Server, (S) Standard (for unlimited hosts), Fnd - vCenter Server Foundation (limited to 3 vSphere hosts) + S&S - Subscription and Support for 1 year, (P) Production: 24 Hours/Day 7 Days/Week 365 Days/Year; (B) Basic:12 Hours/Day Monday-Friday.
The vSphere client (for single server management) is free.
Licensing details here: http://www.vmware.com/files/pdf/vsphere_pricing.pdf
Pricing here: http://www.vmware.com/products/datacenter-virtualization/vsphere/pricing.html