I would recommend rolling your own. Use the sharethis api or addthis. Then you can use get_permalink(); for the url parameter.
function wpu_share() {
$url = get_permalink();
$title = get_the_title();
$add_this = 'st_url="'.esc_url( $url ).'"'; ?>
<span class='st_facebook_large' <?php echo $add_this; ?> displayText='Facebook'></span>
<span class='st_twitter_large' <?php echo $add_this; ?> displayText='Tweet'></span>
<span class='st_linkedin_large' <?php echo $add_this; ?> displayText='LinkedIn'></span>
<span class='st_email_large' <?php echo $add_this; ?> displayText='Email'></span>
<?php }
add_action('wp_footer', 'wpu_share_js' );
function wpu_share_js() { ?>
<script type="text/javascript">var switchTo5x = true;</script>
<script type="text/javascript" src="http://w.sharethis.com/button/buttons.js"></script>
<script type="text/javascript">stLight.options({publisher:"ur-xxxxxxxxxxxx"}); </script>
<? }
Update
You will need to pass a variable to the thank you page that references the post id of the course they signed up for then you can use this to get the right url.
$url = get_permalink( $post_id );
// You will need to pass the post id to the thank you page using a query string or another method.
To use a query string append ?id=$post->ID to the end of the redirect to the thank you page. Then on the thank you page:
if (isset( $_GET['id'] ) $post_id = (int) $_GET['id'];
For security make sure you use esc_url() where ever you are using the $url variable.