I have been advertising on Facebook the last few weeks for four of my projects and in helping a friend. I started with no knowledge at all. While I am not an expert, I have to say that I have gained a lot both in knowledge and in new business. In a nutshell, this is really easy. I probably would not have needed any help at all if I had just dug in, but I found a pretty good document that helped me out. It is titled Facebook Ad Getting Started Guide and it lays out the process very clearly. Beyond that, the document also gives a lot of tips on how to test various types of ads and what works better for most people.
More than anything else, it is easy to target a very specific group of people. For example, in one of the ads I have running we are targeting only Iowans who are interested in being an entrepreneur. Think about who your preferred customer is and try setting up an ad targeting that person. You can reach a lot of people for as little as a dollar a day.