I am not sure if anyone will be able to help me here, but I am interested in getting a used or cheap Cisco router or layer 3 switch to learn how to use IOS, etc. It would be nice for it to be able to work with my cable modem (the cable company finally upgraded the lines on my street), so I would prefer to have to ethernet ports instead of a t1 connector or whatever they normally have. Used, obsolete models are probably my best bet, because I hear that these peices of hardware are pretty expensive new. :-(
Even old, used routers are pretty expensive if you just want to learn the IOS. The 2500 series is probably the easiest one to find on ebay, but expect to pay $300-400+ for an old one. The home based DSL ones (675, 678) do not run the full Cisco IOS, so you don't want them.
You may want to look into router simulator software instead - look at these links: