When we get that bright idea of advertising through the internet we sometimes think.. This is easy and it would not cost me a penny and that we could do it ourselves. While yes this may be true you may not need to spend money on setting up a webpage, you may even do the research on how to make the page rank well on search engines. But count the time you spend on taking up this endeavor. There is the saying that the most valuable commodity is time. Or the saying that time is money. If you would calculate and give yourself a salary for the time you spent on your website you end up spending the same amount or more than hiring a SEO company to do these things for you.
With SEO the earlier you start the better it is to rank the page. But you need the knowledge or expertise on how to get this done. Relevance brings up a page rank. So you also need to spend time to update add media create content and others to make your site up to date and relevant. Building links grows over time. The more links you acquire the better the ranking and visit you will be able to get. Do you still think you can do this alone? Yes probably you may be able to do so but this will take up a lot of time.
There are a lot people who preach that marketing socially through the web is free or low cost. But you have to keep in mind that SEO companies employ numerous experienced content writers to keep their page relevant and media specialists for photo and video requirements. And these companies pay these people big sums of money for their services.
Bottomline is marketing is an investment but by acquiring the services of professional SEO companies I could assure that the money invested will earn returns in profit.