FreeBSD Server

[lpeth]

FreeBSD
Dear Sirs;
I have a 8core, 32 GB ram server I built myself. AMD cpu, with 
Supermicro motherboard. I want to use FreeNAS as a database system, and 
I'm wondering what it will cost to use FreeBSD with FreeNAS. I see the 
Version I would like is $40 for a four CD set, but that does not mean I 
get to use the server version of it. What is the server version going  
to cost?
Sincerely,
Mark T. Evans