This should help you
The license of the NSX is not part of the suite of vCloud Director, the license and the part that is their initial prices are.
1 Perpetual license from $ 5,996
2-Monthly $ 34.00 per virtual machine
For more information on licensing see a channel of VMware
Addition to the previous replies:
If you did already buy vcloud suite there will be a special NSX add-on available:
"NSX for vSphere can be purchased as an add-on to all editions for vCloud Suite and provides advanced networking and security features"