Search engines don't buy products and services. People do.
To sell your products and services online, you need targeted traffic. Search engines will send you targeted traffic, and a lot of it, if you take certain steps.
The first step in your search engine marketing campaign isn't search engine optimization. Your first step is to understand the internet and how to effectively use it to promote your products and services.
The internet is a content driven medium. Searchers are looking for information. They don't want to be sold to. They want value. You can provide this value through the content you write for your website, as well as content you write for your promotions.