Giving away a free informational product such as an e-book, an email series or a mini-course is a popular tactic many affiliate marketers use. Usually, your readers will have to provide their email addresses to receive the product from you. You can then use this to sell to them via email marketing. Additionally, an informational product can generate interest in the actual product you're trying to sell. If your product is popular enough and brings enough traffic to your site, you could also monetize the traffic in other ways, such as AdSense.
A more complex system, pay per lead affiliate programs compensates the affiliate based on the conversion of leads. The affiliate must persuade the consumer to visit the merchant’s website and complete the desired action — whether it’s filling out a contact form, signing up for a trial of a product, subscribing to a newsletter, or downloading software or files.