t is quite simple - there is more people in your market who what traffic then there is spots to advertise. The bottom line is that it is hard because a lot of people are competing for space in your market. So what you have to do is realize that this is the facts and it is not going to chance. If you stop complaining about it and focus on the solutions, you will make more money. http://ideasforppl.blogspot.com/2009/09/why-google-adwords-is-so-hard-what-to.html
the easiest thing to do is learn ppc first, then advertise on google try other advertising networks first