Introduction to the Adwords auction from Google
For all of those people struggling to understand the Google Auction (Adwords) system, here is how it works. At the end, it all depends on how popular your keyword is - the more popular the keyword, the more people bidding on it and hence the higher the Cost Per Click (CPC) you will pay. Its better to let go of the popular keywords and drill down to niche keywords that might give you less impressions but a higher Click Through Rate (CTR).
