There are several options:
At $99, the Linksys Personal VPN Firewall+Router (
BEFVP41) is one of the least expensive solutions. Based on the BEFSR41 Personal Firewall+Router, it comes complete with stateful packet filtering and five Fast Ethernet ports (1 untrusted, 4 trusted). Up to 50 tunnels can be built using IPSec. VPN throughput is limited to 2.5MBit with full 168-bit 3DES encryption.
Slightly over budget at $115, the Asus VPN Firewall+Router (
SL500) also includes five Fast Ethernet ports (1 untrusted, 4 trusted) and a SPF firewall. It also includes more thourough URL filtering and more comprehensive DoS prevention. Although only 5 tunnels can be maintained with the SL500, throughput levels can reach 30Mbit with full 168-bit 3DES encryption.
If you don't mind buying 2nd hand, the Netscreen 5XP-001 and NS-005-001 firewalls offer vastly improved VPN throughput and features. Although only offering two Ethernet (1 trusted, 1 untrusted) ports, it offers a full SPF firewall, URL filtering, application/host bandwidth allocation and shaping, advanced monitoring and logging and support of full 168-bit 3DES encryption. Used prices range from $60 to $150 depending on your luck.
Last, there are several firewall packages for x86 platforms that work as well, if not better, than commercial "all-in-one" products.
M0n0wall, based on FreeBSD 4.10, supports both IPSec and PPTP virtual private networks, offers full NAT and SPI firewall functionality. It comes with a secure web GUI, and offers a host of other features. All it needs is a 486 with 64MB, small HD/CF drive or CDROM, and some fairly mainstream network cards. For less than $100, I swapped out my HDD for a silent CF drive, upgraded to a Coolmax Silent Power Supply (120mm fan) and installed a CPU heatpipe.