bepayper

This plugin adds Payper capabilities in WordPress. 
It works for standard or custom posts, and it can be configured for any type of theme.

Payper widget

Allows to add Payper widget in a Wordpress site.

kartikye

Add a paywall to your articles or blog posts that can be unlocked by users with <a href="https://senddots.com" rel="nofollow ugc">Dots</a> accounts.
Surround the paywalled contents with the <code>[paywall]</code> short code. Example:
<pre><code>Lorem ipsum dolor sit amet, consectetur...

[paywall price="10"]
Paywalled content .... Lorem ipum dolor sit amet, consectetur...
[/paywall]
</code></pre>

Dots Paywall

Paywall your blog posts or articles behind micro-transactions

Payper widget vs Dots Paywall