There are literally thousands of companies out there trying to cash in on the mixture of two things:

1. The general business need for search engine optimization
2. The general business ignorance about search engine optimization

These companies charge low prices (usually) for their services.  The services normally entail looking at the meta tags on a site, offering suggestions, and submitting the website to directories.  The problem is, these services, while inexpensive, are relatively worthless.  They have zero benefit for today’s complex search engine algorithms.