Comment Security appliances (Score 1) 673
I've been working since 1998 on network security and tested a lot of firewalls.
My recomendation: Use hardware appliances like Juniper NetScreen (http://www.juniper.net/products/integrated/), Fortinet (http://www.fortinet.com/) or WatchGuard (http://www.watchguard.com/).
All of them are >U$$100 but that may be the best deal comparing the price to the US$100 per machine you're asking.