SharePoint Portal Server 2003 (SPS 2003), or Microsoft Office SharePoint Server 2007 (MOSS 2007)are not.
However, Widnows SharePoint Services (WSS 2.0 and WSS 3.0) that is what portal and server products are built on, just adding additional features, are. Free as in you need to have Windows Server 2003, so if you have that WSS is free.Of course you can get a full evaluation version as well
What did not work for you out of the box with SharePoint? There is a lot more to setup than just running the installer. Have you tried following any of the online documentation? I work on SharePoint 2003 and MOSS everyday and very rarely does it not work at the end of a setup. Those that have failed for me usually are tied to permissions issues with the service account or database permissions.
Speaking of installing SharePoint. Is there a command line installer or command line install options. I’ve been playing with stsadm.exe and found to easy to set up new sites and security but would really like to be able to script an entire install.