need cheap firewall recommendation

Hi All,

I have a situation where a customer needs a cheap ($300.00-$400.00 appliance firewall. I tried the USR 8200, but it drove me nuts
trying to add custom rules (it asks things in a double negative
fashion and you can never tell what is incoming and what is
outgoing). And, it finally blew out its ROM (it can not be reset
to factory).

Does anyone have a recommendation for a replacement? One that
won't drive someone familiar with iptables crazy?

-T
.