MP Wheeljack stickers for price of postage.
http://reprolabels.com/index.php
http://i.imgur.com/g5eH3Mu.jpg
There are a few other sticker and transfer producers out there now and the site could use some tweaks to make it easier to find where they've categorised official and 3P stuff, but I've had quite a few sets from them over the years and always been very impressed.