Here we have (hopefully) pre-empted some of your questions and answered them
Q/ How long does it take for search terms to show up on Google?
A/ We always recommend that you give it three months, as by that stage we are very confident you will see a difference in your sites rank, so after the three months expire we will put you onto a monthly rolling contract which runs for as long as you feel you are getting the benefits from it. If after three months you feel that it isn’t working you – then you are free to walk away.
Q/ How much will it cost?
Q/ Is it guaranteed to work?
Q/ How do I know which to do SEO or PPC?
Q/ What is the difference between SEO and PPC?
A/ PPC or Pay Per Click Advertising are paid ads that are located on the top, right or bottom of the Search Engine results page. SEO or Organic positions are natural or non-paid results that appear in order down the main part of the page. Organic listings are placed between positions 1-10 on a page 1 (11-20 on page 2 etc) and are arrived at as a result of site optimization or rather SEO (Search Engine Optimization) techniques.