This can be a tough disparity for many starting out marketers. When you start out marketing on the internet do you setup a paid campaign or exchange payment for your time and shoot to optimize your site, and more specifically your individual pages of your site, for SEO?
If you have little money starting out then of course SEO is your only choice. This is where you normally show up for a keyword by making your pages highly relevant to certain keywords.
This will take time and just a bit of money, but no money comes out of pocket for you to physically be on the search engine. This is the difference between PPC and SEO.
Setting up a paid pay per click campaign will allow you to get individual visits to your site for a fee per click through your link on the search engine to your site. You essentially pay to be on the first page of the search engine and every click you get you pay for. Simple, but if not monitored barely it can be very costly.
Time is your largest investment for search engine optimization. In its most basic form search engines love content and relevancy to a keyword. This means that if you are on the first page of Google for the key phrase "stop dog barking" at least one page of your site looks very good to Google for "stop dog barking" and they have ranked you highly for this.
Looking good to a search engine can include many things including what you have written down on your page (the article or message you have), relevant information to stopping dog barking that helps people typing in that keyword, and the general amount of time people spend looking at your site.
There are several other factors that come into play for both pay per click and search engine optimization, but upon differentiating to choose the higher benefit to you, you just need to keep your monetary and time budget in mind.
If you have money to invent then you may want to try out PPC. If you would like to invest your time rather than your money than SEO may be a better bet. Either will take some bit of time to master but both have their strong points in regards benefit to the user.
For most users starting out SEO tend to be the best starting point. That way once you get acquainted with the SEO process you can easily transition over to paying for your traffic.