PPC Marketing is known as Pay-Per-Click marketing. This is where affiliates purchase advertisements on sites such as Google or Yahoo where they choose what keywords they want their advertisements to be displayed for and their maximum bid per click. This is a short term strategy as there is no long term benefit built through PPC marketing, but if you find keywords that cost less per click than you make per click via conversions, then you are in the money. I have used this method to make a very good sum of money in a short period of time. My recommendation would be to use Google AdWords for this, you can find a signup link as well as a much more detailed description at PPC Marketing Guides.