As other posters have said, you really have to know how to set up a campaign, what keywords to use, how to target, the difference between search and display, et

As other posters have said, you really have to know how to set up a campaign, what keywords to use, how to target, the difference between search and display, etcetera. There are all kinds of people delivering services if you want to run a real campaign. I ran a 100 dollar campaign for a university project, it was an interesting learning experience, but it also taught me that for any real campaigns I'd be better off hiring an expert - and they come at all sizes and prices, from independant contractors up to the biggest marketing companies in the world. In my own sample campaign we did get a lot of noise, and a very low click-through rate. We calculated a cost per customer of U$ 8.