You take charge of your SEO. It's easy. Create unique content. Gain credibility with the search engine over time. Learn how to optimize web page components. That's it. Continue to create optimized content as required.
If you want it free, you're going to have to do it yourself. Head over to SEOmoz.org and train yourself. Or you can hire an unpaid intern and have them learn everything. You still shouldn't expect much out of that though, and be careful about letting someone without experience make changes to your website.
Dedicate some time to writing really great content.
Get links to your pages from other trusted websites
Complete all image attributes
Diversify anchor text links
Take note of word count
Avoid duplicate content.