Your plugin is garbage!

Sorry that the notice is not going away for you. Not sure the reason for that, it goes away in all of my testing.

If you’re comfortable editing the plugin’s code, you can simply delete this chunk of code from the plugin, and the notice will go away.

// Display a notice that can be dismissed
function afift_lite_admin_notice() {
    global $current_user;
    $user_id = $current_user->ID;

    // Check that the user hasn't already clicked to ignore the message
    if ( ! get_user_meta($user_id, 'afift_lite2pro_ignore_notice') ) {
        echo '<div class="updated"><p>';
        printf(__('<strong>Thanks for using Auto Featured Image from Title LITE!</strong><br />Use discount code LITE2PRO to get 30% off the <a href="http://designsbychris.com/auto-featured-image-from-title">PRO version</a>! | <a href="%1$s" rel="nofollow">Hide Notice</a>'), '?' . http_build_query(array_merge($params, array('afift_lite2pro_ignore_notice'=>'0'))));
        echo "</p></div>";
        }
    }

add_action('admin_notices', 'afift_lite_admin_notice');

Again, sorry for the trouble.