I am getting ready to up up my website, and would like it listed on Google, can I do this for free, and do I need a robots.txt file and if I do what need to go in to it? so far My robots.txt file looks like this:

User-agent:*
Disallow:/cgi-bin/
Disallow:/privatefolder/
Disallow:/downloads/
Disallow:/important/members.html

is that all I need?

I have never used a robots.txt file.

Check this article out

Adding a site to Google

Consider creating and submitting a detailed site map of your pages using Google Sitemaps. Google Sitemaps is an easy way for you to submit all your URLs to the Google index and get detailed reports about the visibility of your pages on Google. With Google Sitemaps, you can automatically keep Google informed of all of your current pages and of any updates you make to those pages. Please note that submitting a Sitemap doesn't guarantee that all pages of your site will be crawled or included in the search results.

Your robots.txt file currently prevents Google from accessing the listed folders.