look for one in 800 series that has "features" that you are looking for. they are routers but you can use one as firewall. also ... cisco's are (at least the ones i used) can handle crazy enviromental conditions (boiler basement anyone)
The requirements are met. Where did it say failover, 2 firewalls each with their own DMZ? That in and of itself says you'll be spending mucho dinero.
I was just comparing the very far difference in pricing versus features, not suggesting anything. I would assume that he requires a DMZ and for a DMZ you need at least a Pix515. You won't pick one of those up for 500 that is up to date, but you can get them around 1000 bucks. Why DMZ? He mentions he has a box that will service requests by querying another box on the internal network. In fact most of the stuff on ebay requires a smartnet contract if you have any issues or need the latest IOS image and that will run approx 1500. Make sure the one you bid on has an active contract.
Good luck with BSD, I am having issues with SuSE and the damn package manager.
West of House
You are standing in an open field west of a white house, with a boarded front door.
There is a small mailbox here.