Achieving top 10 ranks in natural search engine rankings can boost your traffic for free. You will not have to pay per click. In my case for example, about 80% of our traffic comes from natural (not the paid) search engine listings because we have so many keywords where we rank high. One thing to note however is the changing algorithms of the search engines. With Google's Big Daddy changes for example, you need to be very careful with who you link to. If you engage in a link building campaign be it using an automated software or an SEO company doing it for you, be careful that you link only to sites related to you. Artificial boosting of links is now a no-no. In Matt Cutt's blog explaining how Google views links, he gave an example of why a real estate site suddenly lost pages on Google after Big Daddy was completed. "This is also a real estate site, this time about a Eastern European country. I see 387 pages indexed currently. Aha, checking out the bottom of the page, I see this: Linking to a free ringtones site, an SEO contest, and an Omega 3 fish oil site? I think I’ve found your problem. I’d think about the quality of your links if you’d prefer to have more pages crawled. As these indexing changes have rolled out, we’ve improving how we handle reciprocal link exchanges and link buying/selling." I suggest you read Matt Cutts blog regularly (he's a Google employee) as well as WebmasterWorld.com to get the latest news and fixits with regards to SEO and link building strategies. With regards to choosing the SEO company, I suggest you read the articles below to help you in selecting the right company for you.