itthinx

This plugin integrates the <a href="http://www.itthinx.com/plugins/affiliates/" rel="nofollow ugc">Affiliates</a> with <a href="http://www.jigoshop.com/" rel="nofollow ugc">Jigoshop</a>.
With this integration plugin, referrals are created automatically for your affiliates when sales are made.
The plugin allows you to set a referral (commission) rate so that your affiliates get credited with a referral based on a percentage of each sale’s total net amount.
What you need to use this is all free and ready to go:
<ul>
<li><a href="https://wordpress.org/extend/plugins/affiliates" rel="ugc">Affiliates</a></li>
<li><a href="https://wordpress.org/extend/plugins/affiliates-jigoshop-light" rel="ugc">Affiliates Jigoshop Integration Light</a> (this plugin)</li>
<li><a href="https://wordpress.org/plugins/jigoshop" rel="ugc">Jigoshop</a></li>
</ul>
Install these, set up your shop, decide how much you want to pay your affiliates and start selling!
Feedback is welcome! 
If you need help, have problems, want to leave feedback or want to provide constructive criticism, you can leave a comment here <a href="http://www.itthinx.com/plugins/affiliates-jigoshop-light" rel="nofollow ugc">Affiliates plugin page</a>.
Please try to solve problems there before you rate this plugin or say it doesn’t work. There goes a lot of work into providing you with free quality plugins! Please appreciate that and help with your feedback. Thanks!
You are welcome to <a href="http://twitter.com/itthinx" rel="nofollow ugc">follow me on Twitter</a> for updates on this and related plugins.

Affiliates Jigoshop Integration Light

This plugin integrates Affiliates with Jigoshop.

Freemius

olegabr

Allow your affiliates to create posts and pages on your site. Then if customer visits your site starting from these pages it will be counted as if they came by an affiliation link of the corresponding page author.
<ul>
<li>Dramatically improve your site’s search position.</li>
<li>Make your site a central point of marketing materials, guides and articles for your store.</li>
</ul>
<h4>Free Features</h4>
The <a href="https://wordpress.org/plugins/affiliates-manager/" rel="ugc">Affiliates Manager</a> plugin is supported out of the box.
<h4>PRO Features</h4>
The <a href="https://wordpress.org/plugins/yith-woocommerce-affiliates/" rel="ugc">YITH WooCommerce Affiliates</a> plugin is supported out of the box.

Guest Author Affiliate

Allows your site's content authors to become your affiliates.

Affiliates Jigoshop Integration Light vs Guest Author Affiliate