Hello sk391,
First I would point you to the Cisco certification forum located here:
In the future this is where you will want to post Cisco cert related questions for best response. That said, you will want to practice on both routers as well as switches for the CCNA. As far as types go you want both routers and switches that run IOS. Try the 2950 switches and any routers that can run 12.4 (ie. 2610XM or 3640)... You only need one of these and can supplement the additional routers with 2501 or 2503 models.
A good (inexpensive) CCNA lab would look something like this..
1x 3640 (Router) $100
2x 2501 or 2503 (Routers) $30 total
3x 2950 (Switches) $300 total
1x NM-4A/S or NM-4T (Network Module for 3640) $50
2x Serial Back-to-Back Cables $10 total
TCO (Total Cost of Ownership) = about $500
Everything can be used for your CCNP studies after...
You may wish to decide on a rack as well.. I personally like the Skeletek rack (16U cost me around $100)
Check eBay for these models.. You may find that
has the best deal on the 3640.. $99 plus $5 shipping.. Plus they send you a pack of M&M's and a spiffy business sticker... LoL
I hope that this helps... If you have more questions please follow the link above and post in there... Later!
B Haines
CCNA R&S, ETA FOI