How to Offer a BOGO (Buy One Get One) Discount on the Highest Priced Item in the WooCommerce Cart?

This WooCommerce customization is similar to targeted promotions. In online shops, it is common to find some high values items to go out of trend which is moving slowly. So in such scenarios it is a strategic move to target these products with this kind of BOGO deal. This will benefit in many aspects from increasing overal sales volume to potentially attracting new customers.

Solution: Offer a BOGO (Buy One Get One) Discount on the Highest Priced Item in the WooCommerce Cart

This code offers a discount based on the highest-priced item in the WooCommerce cart , applies it as a discount fee when there is more than one item in the cart.

add_action('woocommerce_cart_calculate_fees', 'ts_apply_discount_based_on_highest_price');

function ts_apply_discount_based_on_highest_price() {
    if (is_admin() && !defined('DOING_AJAX')) return;

    $items_prices = [];
    $items_count = 0;

    // Loop through cart items
    foreach (WC()->cart->get_cart() as $key => $item) {
        // Get the cart item price (the product price)
        $price = wc_prices_include_tax() ? wc_get_price_including_tax($item['data']) : wc_get_price_excluding_tax($item['data']);

        if ($price > 0) {
            $items_prices[$key] = $price;
            $items_count += $item['quantity'];
        }
    }

    // Only when there is more than one item in cart
    if ($items_count > 1) {
        arsort($items_prices); // Sorting prices from highest to lowest

        $highest_item_key = key($items_prices); // Get current cart item key with the highest price

        // Calculate the discount as the price of the highest item
        $discount = $items_prices[$highest_item_key];

        // Apply the discount as a fee to the cart
        WC()->cart->add_fee('Highest Price Discount', -$discount, true);
    }
}

Output

The output shows that as the number of items in the cart increases, the code iterates through each item, identifies the key of the highest-priced items, and then applies the corresponding highest price as the discount amount.
Note: The discount doesn’t get applied when there is only one item present in the cart.

If you are interested to explore similar customizations, then consider targeting the least expensive item and apply BOGO buy one get one discounts to cart cheapest item during a promotion in WooCommerce.