AdSense is a free service by Google. You can make money and earn an income using AdSense if you own a blog or website. Google will display advertisements on your web page. These ads are directly related to what your blog is about, thus visitors will be interested and likely click on them. Every click will make you money. All you have to do is supply the traffic. Google will pay you per click or per 1000 page impressions. A page impression is when a page is viewed by a visitor.