How to to display the text “Call for Price” when the price is 0 or blank

Next code will do the job:

add_filter('woocommerce_get_price_html', 'fbs_woocommerce_get_price_html', 100, 2);

function fbs_woocommerce_get_price_html($price, $product)
{
    if ($product->price <= 0)
    {
        //remove_action('woocommerce_after_shop_loop_item', 'woocommerce_template_loop_add_to_cart', 10);
        //remove_action('woocommerce_single_product_summary', 'woocommerce_template_single_add_to_cart', 30);
        return 'Call for Price';
    } else
    {
        return $price;
    }
}