As far as sims, I'd recommend renting rack space. I've never used Boson, so I can't speak to that. I would have suggested GNS3 but it's very limited in what it can do for switching unless you have some physical equipment, which can also be an inexpensive option if you have room for the equipment. The switches aren't exactly going for an arm and a leg on ebay I haven't used Packet Tracer, but perhaps it's switching sim capabilities are more than what I've seen before on GNS3. Finally, Cisco does now offer "rack space" rentals, but it's (obviously) not free:
https://learningnetworkstore.cisco.com/market/prod/listSubCatLearnLab.se.work?TRGT=85&/nxt/rcrs/=2559&utm_source=cln-hm&utm_medium=bn&utm_content=labs-cln-hm&utm_campaign=Promo-CLL
I also used the Cisco Press Official Exam Guide and Chris Bryant videos. Also, you should take a look at the Cisco Learning Network:
https://learningnetwork.cisco.com/index.jspa?ciscoHome=true
Excellent discussions that help to fill in the blanks and a practice exam to get the brain firing.
Also, if you work in a Cisco shop, it may be worth your while to talk to the boss about the benefit of having a lab. It can be a hard sell with the way most organizations are tightening their wallets, but the worst they can say is no.
