Untitled

add_filter( 'woocommerce_cart_item_price', 'custom_cart_item_price_display', 99999999, 3 );
function custom_cart_item_price_display( $price, $cart_item, $cart_item_key ) {
    $product = $cart_item['data'];

    if ( $product->is_on_sale() ) {
        // Get 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() ) );

        // Calculate discount percentage
        $discount_percentage = round( ( ( $regular_price - $sale_price ) / $regular_price ) * 100 );

        // Format the price display
        $price = '<del>' . wc_price( $regular_price ) . '</del> <ins>' . wc_price( $sale_price ) . '</ins>';
        $price .= ' <span class="discount-percentage">(' . $discount_percentage . '% off)</span>';
    }

    return $price;
}