YITH WooCommerce Frequently Bought Together allows you to suggest a group of selected products on the product page to encourage users to buy more products and offer them at a discounted price also.
The integration with YITH Added to Cart Popup will let the Cart popup open automatically whenever one or more products from the Frequently Bought Together section are added to the cart.
If both plugins are installed and activated, you will be able to enable a new option on the settings page: YITH Plugins > Added to Cart Popup > Settings > Enable for “Frequently Bought Together” button.
This is how the Frequently Bought Together section looks like:
And this is the products added to the popup, including any discount set up through Frequently Bought Together plugin:
To read more about YITH Frequently Bought Together plugin, please, refer to the plugin documentation here.