Custom post types: change “read more” text

Question

Hmm, and what is the difficulty in here? You already have global $post variable in your function. Just use it.

function excerpt_read_more_link($output) {
    global $post;
    $text="Read more";
    if ( $post->post_type == 'MY-CUSTOM-POST-TYPE' )  // change MY-CUSTOM-POST-TYPE to your real CPT name
        $text="Get it now";
    return $output . '<a class="more-link" href="'. get_permalink($post->ID) . '">'. $text .'</a>';
}
add_filter('the_excerpt', 'excerpt_read_more_link');

Of course you can put multiple such if statements in there.