Over the years I’ve used a lot of different pay per click advertising services. There have always been first tier services and then second and third tier services. The first tier pay per click services would be Google Adwords and MSN adCenter. Google is the big one and they reach the greatest number of potential buyers. They can be more expensive and more competitive so be ready to invest more money.
Once you nailed things down with Adwords, then go to MSN adCenter. You can get visitors through here because your ads will show up in Bing and Yahoo. There system is a little harder to use but can get you visitors that you’d miss in Adwords.
Another avenue is to advertise on Facebook. These are the ads that show up on the right side of the page in Facebook. You can gear your ads to certain locations and demographics.