There is nothing more important than SEO for your website/business website/web-based business.
This day and age there is practically no way to "cheat" like in the old days, when you could load your pages up with meta tags and bolster your ranking. Google is too smart and you really have to have solid, targeted content for your keywords.
A couple SEO firms quoted me around $1500 to optimize my site with some pretty impressive references. I have yet to pull the trigger but very strongly considering it in the near future.