IMHO, the 2500 series routers are substandard for taking the CCNA. You’d be better off buying Boson’s router simulator and it will cost less than purchasing a router on E-Bay ($150.00 vs $420.00). The Boson router simulator can do a lot more than the simple router and allow you to connect multiple routers and switches together (virtually, of course). They claim 47 different types of routers and switches. Plus, the Boson route gives you tests and simulations to work through.
Here’s a link to the Boson site:
Enjoy and good luck,