Search Engine Optimization (SEO) organizes the pages on the website for both the search engine spiders and the visitors to the site. Search engines look for your site based on combinations of words on the site. The more words you have on your site, the easier it is to find. That's why a blog is so much more effective than a static webpage.
Proactively seek out the free listings first. The ones that are selling ads will seek you out and beg you to spend. Personally, I would hire a competent social media/marketing consultant first and foremost before I paid for advertising.