[cisco-voip] Least expensive router that can run CUBE

[Bill Simon]

My disclaimer to this newbie question is that I'm not a router guy in 
any way and have little understanding of the router product line.

What's the least expensive piece of equipment that can run Cisco Unified 
Border Element?

On the CUBE product page I see this list:

Cisco Unified Border Element is an integrated Cisco IOS Software 
application that runs on:
Cisco 2800 Series Integrated Services Routers
Cisco 3800 Series Integrated Services Routers
Cisco 7200VXR Routers
Cisco 7301 Routers
Cisco AS5350XM Universal Gateway
Cisco AS5400XM Universal Gateway

Just looking for a test box with fast ethernet connectivity, no T1 or 
analog cards or anything.