Banner ads are exactly what you might expect. You insert a banner with a catchy tagline or graphic at the top, side or bottom of somebody else’s website. If people click on the banner, they come to you. In turn, you could put a banner ad for an affiliate product on your site for readers to click.

Affiliate marketing is a great way to have multiple income streams. whenever you promote some sort affiliate program on your blog, you write a review of a product or a service and in exchange you are paid a commission of its price once you make a sale.
ClickBank and JVZoo are two marketplaces that have affiliate programs to offer.