Brian Layman

<p>This plugin allows the creation and display of custom sidebars for any page (or post) on your site. On each page, you can choose which of your current theme’s sidebars will be replaced. The replacement works for all descendants of a replaced page.</p>
<p>In this fashion you can:<br />
1. Easily create a CMS like site with unique sidebars for every page, even if your theme doesn’t support it.<br />
2. Create a sidebar with a Cart widget that displays on store pages created by the WP-E-Commerce page, but not anywhere else on the site.<br />
3. Use parent pages to create themed areas of your site, without creating custom page templates.</p>
<p>This plugin is compatible with every theme and all widgets because it hijacks your theme’s sidebars instead of replacing them.</p>
<h3>Use</h3>
<ol>
<li>Edit a page or create and save one. It must at least have a title.</li>
<li>In the ?Custom Sidebar? section, check ?Activate a custom sidebar? and select the sidebar to replace.</li>
<li>On the Appearance->Widgets screen, place the widgets on the newly created sidebar that matches your post. </li>
</ol>
<p>That?s it. No code. No CSS changes. No custom templates.</p>
<p>This video describes the usage of the plugin:<br />
     <span class="embed-youtube" style="text-align:center; display: block;"><iframe loading="lazy" class="youtube-player" width="640" height="360" src="https://www.youtube.com/embed/_U2XfrU7nZQ?version=3&rel=1&showsearch=0&showinfo=1&iv_load_policy=1&fs=1&hl=en-US&autohide=2&wmode=transparent" allowfullscreen="true" style="border:0;" sandbox="allow-scripts allow-same-origin allow-popups allow-presentation allow-popups-to-escape-sandbox"></iframe></span></p>


Per Page Sidebars

The Per Page Sidebars (PPS) plugin allows blog administrators to create a unique sidebar for each Page. No template editing is required.

Brady Vercher

Cedaro

<p>Designed for simplicity and flexibility, Simple Page Sidebars gives WordPress users, designers, and developers the ability to assign custom sidebars to individual pages–without making any template changes. Existing sidebars can also be assigned in quick edit and bulk edit modes, helping save you time.</p>
<p>In contrast to some of the more complicated plugins available, Simple Page Sidebars aims for basic, core-like functionality and integration that’s easy to use without polluting your admin panel. And due to the way sidebars are saved, it utilizes built-in WordPress caching, so your site won’t be bogged down with additional queries.</p>
<p>Simple Page Sidebars also ships with a “Widget Area” widget for pulling all the widgets from one sidebar into another.</p>
<h3>Benefits</h3>
<ul>
<li>No more site-wide, generic sidebars. Each page (or section) can have its own widgets.</li>
<li>Complete control over the names of your custom sidebars.</li>
<li>Assign the same sidebar to multiple pages.</li>
<li>Modify a page’s sidebar without creating an unnecessary revision.</li>
</ul>
<h3>Advanced Usage</h3>
<p>If you want to assign custom sidebars to archive pages or replace multiple sidebars per page, this plugin likely won’t be the best solution. However it’s flexible enough to handle a wide range of page-based use cases. It can even be configured to work with Custom Post Types by adding a couple lines of code:</p>
<pre><code>function myprefix_init() {
    add_post_type_support( '{{post_type}}', 'simple-page-sidebars' );
}
add_action( 'init', 'myprefix_init' );
</code></pre>
<h3>Additional Resources</h3>
<ul>
<li><a href="https://wordpress.org/support/view/plugin-reviews/simple-page-sidebars#postform" rel="ugc">Write a review</a></li>
<li><a href="https://github.com/cedaro/simple-page-sidebars" rel="nofollow ugc">Contribute on GitHub</a></li>
<li><a href="https://twitter.com/cedaroco" rel="nofollow ugc">Follow @cedaroco</a></li>
<li><a href="https://www.cedaro.com/?utm_source=wordpress.org&utm_medium=link&utm_content=simple-page-sidebars-readme&utm_campaign=plugins" rel="nofollow ugc">Visit Cedaro</a></li>
</ul>
<h3>Notes</h3>
<h3>Custom Loops</h3>
<p>If your page has any custom loops or queries, they need to be followed by <code>wp_reset_query()</code>, otherwise the global <code>$post</code> variable will no longer reference the correct post and by the time the sidebar is displayed, Simple Page Sidebars won’t know which page is being viewed, possibly leading to an unexpected sidebar being displayed.</p>
<h3>Theme Sidebars</h3>
<p>Some themes register different sidebars for their page templates, which means there isn’t a default sidebar that can be replaced. To use Simple Page Sidebars in this instance, you can create a child theme and force page templates with custom sidebars to use the default sidebar.</p>


Simple Page Sidebars

Initially I was disappointing it didn't work on custom post types, but then bothered to read the instructions.
The developer had bothered to put down exactly how to do this:
function myprefix_init() {
    add_post_type_support( '{{post_type}}', 'simple-page-sidebars' );
}
add_action( 'init', 'myprefix_init' );
Works a treat! Very flexible. Great job.



Works great

Easy to understand how to use it and does exactly what it says. Great plugin.



Works great!

Easily assign custom, widget-enabled sidebars to any page.

Per Page Sidebars vs Simple Page Sidebars