The CD costs 5 EUR plus shipping. LinuxLand will sponsor 1 EUR of each sold copy for the production of additional CDs at OGo.
The OGo Knoppix is the fastest way to get a running OGo demo, as it requires no installation - just boot from it and you get a working system, including a Cyrus IMAP4 server.

Get it in the LinuxLand online shop. Unfortunately it seems to be in German only, but if you get through, LinuxLand is shipping outside Germany!