Change price font to h2 and green - /wp-content/themes/YOURTHEME/woocommerce/single-product/price.php

price.php

<?php
/**
 * Single Product Price, including microdata for SEO
 *
 * @author              WooThemes
 * @package     WooCommerce/Templates
 * @version     1.6.4
 */

if ( ! defined( 'ABSPATH' ) ) exit; // Exit if accessed directly

global $post, $product;
?>
<div itemprop="offers" itemscope itemtype="http://schema.org/Offer">

        <h2><font color="green"><?php echo $product->get_price_html(); ?></font></h2>

        <meta itemprop="price" content="<?php echo $product->get_price(); ?>" />
        <meta itemprop="priceCurrency" content="<?php echo get_woocommerce_currency(); ?>" />
        <link itemprop="availability" href="http://schema.org/<?php echo $product->is_in_stock() ? 'InStock' : 'OutOfStock'; ?>" />

</div>
~