Google uses an algorithm to determine the search engine results (SERPS). The algorithm is based upon certain factors that include keyword density, Meta Tags, anchor tags, image tags, back links, etc etc etc.

If your site is optimized for specific keywords than you will rank better in the search engines. There are many factors but onsite optimization is a must. You can research and fine out the information yourself or hire and SEO. I have put together some Free Basics on www.seo4dummies.com

Overture shows you the bid price of certain keywords. Wordtracker show you the amount the term is searched. You can use www.nichebot.com a free tool to see all this at once.

You can research keywords free online with these various tools.

www.nichebot.com ( my personal SEO Favorite)

http://www.webmasterautomation.com/cgi-bin/keywordtool.cgi

http://www.keyworddensity.com ( Keyword density analyzer )

Adsense / Adwords.

Google Adwords have a bid price to display certain