I don't know squat about asp, but I know there are plenty of open source PHP CMS systems available. Two of the leaders being
www.phpnuke.org and
www.postnuke.com. There is also xoops, mambo, and a few more I have been hearing more and more about.
I imagine there are some free asp solutions out there that will be just as good (if not better) than their commercial counterparts.
Here is a link to hotscripts' asp software page (many are free):
http://www.hotscripts.com/ASP/Software/index.html
I just hate to see people pay for software when an open source package is available, especially a church. Maybe someone with more asp knowlege will be able to recommend something.