How to Implement a WooCommerce BOGO: Buy a Fixed Total Quantity from Category X or Y, Get One Free from Category Z?

In this post, you can implement a BOGO promotion similar to one of our previous post which will implement a BOGO deal to buy a fixed total quantity from both categories X and Y, get one free from category Z. But here, we will be providing an option among the categories X and Y from which customers need to buy a fixed total quantity. The difference is that if any one of the categories meets the required quantity threshold then the free product is added from Category Z.

add_action('woocommerce_before_cart', 'ts_cart', 10);

function ts_cart() {
    // Initialize variables
    $category_ids_to_buy = array(50, 65); // Categories X and Y
    $free_category_id = 63; // Category Z
    $required_quantity = 3; // Total combined quantity required to trigger free product

    // Initialize counters for each category
    $category_counts = array_fill_keys($category_ids_to_buy, 0);

    // Update counters based on items in the cart
    foreach (WC()->cart->get_cart() as $cart_item) {
        $cart_product_cats_ids = wc_get_product_term_ids($cart_item['product_id'], 'product_cat');
        foreach ($category_ids_to_buy as $cat_id) {
            if (in_array($cat_id, $cart_product_cats_ids)) {
                $category_counts[$cat_id] += $cart_item['quantity'];
            }
        }
    }

    

    // Check if any category meets or exceeds the required quantity
    foreach ($category_counts as $category_id => $count) {
        if ($count >= $required_quantity) {
            // Get a free product from the specified category
            $free_product_id = ts_get_free_product_from_category($free_category_id);

            // If free product ID is not null, add it to the cart
            if ($free_product_id) {
                // Add free product to the cart
                WC()->cart->add_to_cart($free_product_id);
               
            }
        }
    }
}

function ts_get_free_product_from_category($category_id) {
    // Implement this function to dynamically get a free product ID from the specified category
    $args = array(
        'post_type' => 'product',
        'posts_per_page' => 1,
        'tax_query' => array(
            array(
                'taxonomy' => 'product_cat',
                'field' => 'id',
                'terms' => $category_id,
            ),
        ),
    );

    $products_query = new WP_Query($args);

    if ($products_query->have_posts()) {
        $products_query->the_post();
        $free_product_id = get_the_ID();
        wp_reset_postdata();
        return $free_product_id;
    }

    return null; // Return null if no free product is found
}

add_action('woocommerce_before_shop_loop', 'display_bogo_notice');

function display_bogo_notice() {
    echo '<div class="woocommerce-message">Choose any 3 from category "Smartphone" or "Laptops" and get one free product.</div>';
}

Output

To make customers aware of the BOGO Promotions running in your online store you can add a notice to prompt them and clearly mention the categories for which the BOGO offer is applied as shown below.

When customers choose the products from Category X and Category Y, and if the minimum required quantity of 3 is met, one of the free product from Category Z will be fetched and automatically added to the cart.

In the same way, you can also offer discounts on category Y when purchasing category X within a specified quantity range in WooCommerce.