I'm new

I'm new to wordpress however I'm wanting to build a site for someone else, I also plan on building a site for myself. A couple maybe depending on how I get the hang of it. Do I have to start more than one wordpress account for each site and pay the yearly for each site to have access to the tools I will need to develop the site. Or once I develop the site can I migrate it over to his own account. I'm trying to avoid spending too much on production but I want to create something really nice for them as well. How do I go about creating sites for separate clients. Is there somewhere I can find this info cause with everything I find I find something new and my brain is about to explode.