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.

MattGeri

Pigeon.io

sabramedia

Pigeon is paywall software that allows you to hide your content from users by specifying paywall rules. It offers account management and subscription based billing for your readers and subscribers. Enable this plugin to start using the Pigeon Paywall on your WordPress website.
An account on <a href="https://pigeon.io" rel="nofollow ugc">Pigeon.io</a> is required for this plugin to function. Your paywall rules and account management are setup and managed inside your Pigeon.io account. This plugin enables the JavaScript scripts and widgets required to block your content from non-subscribers based on the rules you’ve setup in your Pigeon.io account. Please read the <a href="https://pigeon.io/terms-of-service" rel="nofollow ugc">terms of service</a> and <a href="https://pigeon.io/privacy-policy" rel="nofollow ugc">privacy policy</a> for Pigeon.io.

Pigeon Paywall

The official Pigeon Paywall plugin for WordPress

Payper widget vs Pigeon Paywall