Upselling is a sales technique where the salesperson encourages a more expensive purchase by a customer by persuading them to get an upgraded version of an item or to purchase add-ons. Remember our food processor example? That food processor could probably be best used with a book of recipes, which also can be purchased at the same company’s website.
One of the cool things about Google AdSense is that it's so easy to get set up. If you have a blog or website, you can sign up for a free Google AdSense Account. From there, Google will give you a unique code that you will paste onto your website. Google takes it from there, tracking your page views, traffic, and earnings on your behalf. There is no upkeep or maintenance to get this thing going, which makes it a no-brainer if you have a website already.