You join categoryclicks.com for free. Paste the given banner code in your blog's sidebar. The code is given to you based on the category of your blog. So, you must clearly specify the category under which your blog comes in.
For every click that is generated on the banner you place, you get half a click. For example, if the banner gets clicked 100 times, you are credited with 50 visits to your blog.
Here is a sample banner that is given by categoryclicks.com.
Choose a category for your site, and they will send you a steady stream of clicks from other sites in your category.