Display Old Price Struck-Through Next to New Promotional Price

Code

<?php
// Hook into WooCommerce to modify the way prices are displayed on product pages
add_filter('woocommerce_get_price_html', 'wp_dudecom_display_strikethrough_old_price', 10, 2);

/**
 * Display the old price with a strikethrough next to the new sale price.
 *
 * @param string $price The original price HTML.
 * @param WC_Product $product The WooCommerce product object.
 * @return string Modified price HTML with strikethrough for old price.
 */
function wp_dudecom_display_strikethrough_old_price($price, $product) {
    // Check if the product is on sale
    if ($product->is_on_sale()) {
        // Get the regular and sale prices
        $regular_price = wc_get_price_to_display($product, array('price' => $product->get_regular_price()));
        $sale_price = wc_get_price_to_display($product, array('price' => $product->get_sale_price()));

        // Format the prices
        $regular_price_html = wc_price($regular_price);
        $sale_price_html = wc_price($sale_price);

        // Return the formatted price with strikethrough for the regular price
        $price = '<del>' . $regular_price_html . '</del> <ins>' . $sale_price_html . '</ins>';
    }

    return $price;
}
?>