This plugin will add a new meta box to your posts and pages allowing you to mark posts that require users to login. Visitors trying to view the post, will be asked to login. 
<a href="https://i.imgur.com/ghvTt.png" rel="nofollow ugc">See a screenshot</a>

Simple Content Restriction

Ask your visitors to login if the post is marked as visible only to registered users.

Automattic

WooCommerce

Manos (a11n)

SomewhereWarm

Jason Kytros

Looking for a way to restrict product access in WooCommerce? Don’t want to set up a full-fledged <a href="https://woocommerce.com/products/woocommerce-memberships/" rel="nofollow ugc">memberships</a> site?
This tiny plugin allows you to restrict access to any WooCommerce product, depending on the ownership or purchase of other, required products.
Features:
<ul>
<li>Conditional product access based on the ownership and/or purchase of other required products.</li>
<li>Support for “ownership”, “purchase” and “ownership/purchase” dependency types.</li>
</ul>
Developers can checkout and contribute to the source code on the plugin’s <a href="https://github.com/woocommerce/woocommerce-product-dependencies/" rel="nofollow ugc">GitHub Repository</a>.
Important: Requires WooCommerce 2.2+. WooCommerce 3.0+ or higher recommended.
Like this plugin? You’ll love our official WooCommerce Extensions:
<ul>
<li><a href="https://woocommerce.com/products/product-bundles/" rel="nofollow ugc">WooCommerce Product Bundles</a></li>
<li><a href="https://woocommerce.com/products/composite-products/" rel="nofollow ugc">WooCommerce Composite Products</a></li>
<li><a href="https://woocommerce.com/products/conditional-shipping-and-payments/" rel="nofollow ugc">WooCommerce Conditional Shipping and Payments</a></li>
<li><a href="https://woocommerce.com/products/product-recommendations/" rel="nofollow ugc">WooCommerce Product Recommendations</a></li>
<li><a href="https://woocommerce.com/products/all-products-for-woocommerce-subscriptions/" rel="nofollow ugc">All Products for WooCommerce Subscriptions</a></li>
</ul>
<h3>Documentation</h3>
Dependencies are evaluated when customers attempt to add a product to their cart. If validation fails, the product cannot be added to the cart and a notice is displayed. In order to evaluate “Ownership”-type dependencies, customers are prompted to log in.
<h4>Creating Dependencies</h4>
To add dependencies to a product:
<ul>
<li>Go to the Product Data > Dependencies tab.</li>
<li>Use the Product Dependencies field to search for and add some products and/or variations.</li>
<li>Choose a Dependency Type.</li>
<li>Update to save your changes.</li>
</ul>
The “Ownership” dependency type is evaluated by checking if the customer has purchased a required product in a previous order. The “Purchase” dependency type requires the customer to have a required product in the cart in order to purchase the dependent one.
<h4>Ownership vs Purchase</h4>
The plugin allows you to select between 3 different dependency types:
<ul>
<li>Ownership: Access is granted only to customers that already own any of the products added to the Product Dependencies field.</li>
<li>Purchase: The product can be purchased only in combination with any of the items added to the Product Dependencies field. Ownership is not taken into account.</li>
<li>Either: Access is granted with ownership or purchase of any item added to the Product Dependencies field.</li>
</ul>

WooCommerce Product Dependencies

WooCommerce Product Dependencies is a well-built plugin that does one thing really well. It allows you to restrict the purchasing of a product unless certain other products have been purchased previously, or you have certain other products in your cart (and purchase them alongside the main product).

The UI fits right into the WooCommerce admin design. Super-simple options. Very clear how to use it. Great documentation on the WordPress plugin page.

And Jason provided fast & thorough support when I reached out with a question.

I'd highly recommend this plugin for anyone looking to set up WooCommerce product dependencies.

Works perfectly. Designed well. Does one thing really well.

Restrict access to any WooCommerce product, depending on the ownership and/or purchase of other required products.

Simple Content Restriction vs WooCommerce Product Dependencies