If you want to make money from your WordPress site, or you have the intention of making a website to generate an income, the collection of free plugins on this list can help you with your goals.
Ad Injection helps you insert adverts anywhere around the existing content of websites hosted on WordPress. The adverts can be from any of the popular ad networks like Google AdSense, Amazon Associates, ClickBank, TradeDoubler, etc.
WordPress Simple Paypal Shopping Cart
WordPress Simple Paypal Shopping Cart allows you to add an 'Add to Cart' button for your product on any posts or pages. This simple shopping cart plugin lets you sell products and services directly from your own wordpress site and turns your WP blog into an ecommerce site.
GoCodes WordPress Plugin
GoCodes WordPress plugin is one of the best free plugin for Affiliate marketers. This plugin will help you to hide and keep a track of number of clicks on your affiliate link.
Quick Adsense is an Ads management WordPress plugin. It offers a quicker & flexible way to insert Adsense or any Ads code into a blog post. Besides, it can randomly place the Ads anywhere within a post. It comes with a simple setting page, and it does not overwhelm you with complicated customizable options.
AmazonSimpleAdmin lets you easily integrate Amazon products into your wordpress pages. By using the template feature, you can present the products in different styles on different pages.