itthinx

This plugin integrates <a href="http://www.itthinx.com/plugins/affiliates/" rel="nofollow ugc">Affiliates</a> with <a href="http://www.ecwid.com/" rel="nofollow ugc">Ecwid</a>.
With this integration plugin, affiliates are credited with referrals automatically after a customer has made a purchase through the online store powered by Ecwid.
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.
Required:
<ul>
<li>An <a href="http://www.ecwid.com/" rel="nofollow ugc">Ecwid</a> account with Order API and Instant Order Notifications API access enabled – this will not work with free accounts.</li>
<li><a href="https://wordpress.org/extend/plugins/affiliates" rel="ugc">Affiliates</a></li>
<li><a href="https://wordpress.org/extend/plugins/affiliates-ecwid-light" rel="ugc">Affiliates Ecwid Integration Light</a> (this plugin)</li>
</ul>
Optional:
<ul>
<li>The <a href="https://wordpress.org/extend/plugins/ecwid-shopping-cart/" rel="ugc">Ecwid Shopping Cart</a> plugin for WordPress</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-ecwid-light" rel="nofollow ugc">Affiliates Ecwid Light 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 itthinx on Twitter</a> for updates on this and related plugins.

Affiliates Ecwid Light

This plugin integrates Affiliates with Ecwid.

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 Ecwid Light vs Guest Author Affiliate