SEO stands for Search Engine Optimization. There are a whole range of optimization techniques that need to be done on and off your site, including social sites etc to get your site to rank high in the Organic listings of Google. For SEO services you would pay the agency who implements all these optimization techniques but the traffic you get from Google is free traffic. However this method can take from 6 months to a year to see any significant increase in traffic so if a company is running on a small advertising budget it can be quite expensive to invest money and only see results further down the line.
PPC stands for Pay Per Click. In a nutshell, We would submit to Google a range of keyword phrases that people would put into Google and then we would create a compelling ad like the ones below and tell Google whenever someone puts in this keyword show this ad. You don’t pay Google when your ad is shown, only when your ad is clicked on. You can then measure your results by installing tracking code to see out of all the clicks you have received how many actually made an enquiry and then optimize your campaigns by increasing the amount you are willing to pay for the higher performing keywords.
Large companies would general have an integrated approach and used SEO and PPC to get the advantages of both. For smaller companies who want to see quicker results then we would recommend PPC and then SEO at a later stage.