inexpensive firewall

I have been tasked to setup a firewall for a non-profit group. I have been searching for some low cost good firewall solutions to implement. Any ideas?

Check out the following links and if you have any prooblems we wold be glad to help
m0n0.ch/wall/
www.ipcop.org/

DaLight always waxes lyrical about IPCop - in fact I'm amazed The_Bezerker managed to beat him to the mention! It is good though.
Just as a thought - do you want a separate firewall device like IPCop or would a router with a decent hardware firewall built in be sufficient?

My ears were burning as I heard my name being taken in vain!!