Multiple domains per host?

Im on the domaincrazyinsane hosting plan, and I own one domain,

I want to set up a hosted domain for my friend using my plan and I want it to be transparent.

ex: will look to as its base directory, but will not change the browser url. And should also be functional.

Im looking to pay nothing beyond the domain reg fee - Anyone have a step by step of this process?

This is actually easier than you think.

The Crazy Domain Insane plan allows you to fully host three domains. For just the cost of domain registration (here or anywhere), you can add the domain to your plan and not have to play around with redirects or mirrors.

Go into your webpanel at Domains > Add Domain and you can add the domain.