SharePoint

I have been tasked with making Sharepoint available to the project management division of my company. I was told they want to stand SharePoint up for about 50 users inner network only. My first question (of several I am sure)how much will it cost, what exactly do i need. Do I need SharePoint Server 2007 & then copies of Sharepoint Services 3.0 & Designer?

Any help will be very appreciated!