With website templates you can get the best of both worlds. You can get something that is low-priced, was made by a professional developer, and is going to have at least a semi-professional look that should suit you just fine. These designs have been developed exclusively for professionals and individuals who want a simple solution. You will be able to add your own images, content, etc. to the site. As far as price goes though, it can definitely fluctuate. You can find low-priced templates or higher priced website templates.
The two main parts of a template are the content management code and the theme. These should be kept separate so that the theme can easily be changed without affecting the structure. For example, the styles should be defined in an external style sheet and not embedded in the HTML code of the pages. The structure of a website will be defined by a set of templates. It is good practise to make the templates modular rather than having page templates containing all the code for each page. This allows site-wide changes to be easily applied. For example, the footer may be mostly identical between pages.