For CCNA, I would recommend using Packet Tracer which is completely free. You simply do a quick Cisco Learning Network course and then can download. For CCNP intro Packet Tracer would get you pretty far but then you would want CML-PE to move into advanced labs / routing topics, etc.
You do not have to be a paid Net Academy student to get Packet Tracer any more. I just ran through this to get the latest MAC version to see what changed.
How to download Packet Tracer To download Packet Tracer, follow these steps to create your Networking Academy registration:
Click the 'Enroll to Download Packet Tracer' button Enroll in the Introduction to Packet Tracer course Complete your Networking Academy registration Launch the Introduction to Packet Tracer course Download instructions are found within the course