Alexis , Google Cash System is just a way to drive traffic to your site and it makes absolute sense.

Lets take a look at it like this - You use PPC Search Engine to promote Corey Rudl's Marketing Book. The cost per click is 10 cents, the conversion rate is 100:1 and the commission that you earn per sale is $65 .

Your Investment for Making one sale - $10.

The Profit that you make per sale - $55 .

Makes Sense! But the points to consider while starting this sort of campaign are the conversion rate and commission you earn.

Just don't forget that age old saying - To make a dollar never spend more than 99 cents.

And , If you start a campaign like this for yourself and you need any sort of help promoting it - We are right here to help you!