SEO (Search Engine Optimisation) is a technique we use to achieve first page positions organically, this means your website gets to the top of the page of Google and stays their indefinitely, No matter how many times you are clicked! the flip side is that SEO is a long term solutions and in some cases can take 4-6 months to achieve positions, especially in more competitive markets.
PPC (Pay Per Click) is the process of paying Google to put you at the top of the pages in the Ads section. This works exactly as described it is a pay per click system, meaning every click costs you money. Typically a customer would apply a budget to their PPC campaign and once its gone, you disappear off the first page. The flip side of PPC is that no matter who clicks you it will cost you money, whether they are a customer, tyre kicker or even a competitor.
Both have their merits but Power Media come down on the side of SEO, although PPC is is fast, it is also very expensive and allows your competitors to remove you off Google by repetitively clicking your listing. The main reason SEO is preferable is that your customers are far more likely to click a natural listing over an advertisement. This yields a better ROI for SEO.