WordPress Inquiry

I see many templates for WordPress and would like to be able to use scripts etc from to make working site…..I understand that WordPress is free is that correct..?
What do I need to make a paid script work..as id I had created the site and or can I make changes to the site once created.
TIA
Answer #1
Wordpress is free blogging script, there are many free templates available for all purposes so there is no need to buy anything, both could be done, you can create a site or you can make changes once creation is done,
Answer #2
Does that mean I can add themes to my unpaid for site..?..any idea
Answer #3
yes you can add themes, plugins everything, to your wordpress blog