I am now reading some info on how to make money with wordpress, i wanted to start a small blog site, and put some adsense. Maybe that will be a great start.
You may want to check out Headway themes, they are a direct competitor to the Thesis theme and offer a drag and drop web builder, which Thesis does not. It is everybit as powerful and SEO friendly as Thesis.
If you want to build a website yourself, check out Weebly (weebly.com). Super easy drag and drop builder and very seo friendly.
If you are talking about using WordPress.com vs WordPress.org. The themes you see are the ones you can choose from although you can buy the CSS code to some of them for some minor tweaking. :)