I have a DrayTek Vigor 2920n for sale, which has 3 total WAN ports (2 Ethernet WANs and 1 cellular WAN), available for $180 or your best offer. Here's an overview:
Draytek's Vigor 2920n model includes 4 gigabit LAN ports, two Ethernet WAN ports (including gigabit WAN), 1 cellular WAN port, and 802.11n Wi-Fi. With support for Jumbo Frames and IPSec VPN tunnels, the 2920n is an inexpensive way to add enterprise-class features to your corporate or home network.
Draytek's Vigor 2920n model includes 4 gigabit LAN ports, two Ethernet WAN ports (including gigabit WAN), 1 cellular WAN port, and 802.11n Wi-Fi. With support for Jumbo Frames and IPSec VPN tunnels, the 2920n is an inexpensive way to add enterprise-class features to your corporate or home network.