sdesalas

This plugin allows WordPress to block over 95% of spam comments using a time-based hash.
This allows for a minimum sanity check and yet should remove almost all spam comments 
without the need to sign up to any third party APIs.
The plugin has been tested in real world conditions for around 12 months. It will not block 
real comments and it is pretty effective against spam, however it only uses a very simple 
algorithm and for that reason some spam comments may still make it through.

WP Simple SpamCheck

This plugin allows WordPress to block over 95% of spam comments using a time-based hash.

Andrew Munro

This plugin requires <a href="https://wordpress.org/plugins/woocommerce/" title="WooCommerce" rel="ugc">WooCommerce</a>. It allows the site owner to prevent a product from being purchased by enabling a checkbox. It also allows you to override the message on a per-product basis. This will be useful for when you want to let customers know a product is only available in-store but still have the product listed on your website.
How does it work?
This is a very simple plugin that hooks into WooCommerce’s woocommerce_is_purchasable filter. When a product is deemed unpurchasable the “add to cart” button on the main product listing is replaced with a “read more” button. When the customer views the single product page they are shown a message that the product is not available for purchase and the add to cart buttons are removed.

WP Simple SpamCheck vs Prevent Purchase for WooCommerce