How does Adwords work?

Adwords account for about 20-25% of the traffic that leaves Google, 70-75% of traffic leaves Google through the natural listings that are achieved through SEO.
Adwords work on a cost per click (CPC) system so you pay for every single visitor to your website
The rank you achieve is based on an auction, the more you pay per click, the higher you will rank which means there is no fixed cost
The average website has a bounce rate of 48% which means that the average website loses 48% of its traffic within the first 10 seconds.
The average Google Adword campaign has a 3% click through rate, so for every 100 searches of a particular phrases, expect to get 3 visitors to your website
A successful Adword campaign should expect to have a click through rate of 10-15%.