Not sure if this is available in your area, but have a look at the $210 USD Netgate m1n1wall boxes:
Zero moving parts means no fan noise and an extended lifetime.
The Netgate m1n1wall 2E system utilizes PC Engines ALIX 2D2 network board with 2 LAN and 2 miniPCI slot and your choice of the latest m0n0wall or pfSense software which provide many of the features of expensive commercial firewalls.
Appliance Features:
- ALIX.2D2 System Board with
- 500 MHz AMD Geode LX800 CPU
- 2 10/100 Ethernet ports (VIA VT6105M 10/100)
- 2 miniPCI slot for future expansion (VPN Acceleration, wireless, etc.)
- 2 USB ports
- 256 MB DDR DRAM
- Black ALIX case with Ethernet and USB cutouts
- 2GB Sandisk Ultra II CF Card pre-loaded with m0n0wall or pfSense
- US Plug Style 120 VAC/DC 15V 1.25A 18W Switching Power Supply
- Assembled and tested
Software Features:
The m1n1wall arrives
pre-loaded with your choice of m0n0wall or pfSense software. If you prefer, reload the CF card with your own operating system / software to support your application. Possibilities include FreeBSD, NetBSD, OpenBSD, OpenWRT, Voyage Linux, STYX, iMedia ALIX Linux, Fluxbuntu, fli4l, Zeroshell, Ikarus OS, Embed-it, Mikrotik RouterOS.
(forum.pfsense.org).