Here we list great sources for all the Marketing Collateral that helps build you up as a brand and show that you are serious about your message
Postcards are a great way to promote your books. You can design them for mailing directly (i.e. with a stamp) or as an insert to go into a book, envelope, or handed out. I've had great success with VistaPrint but you should Google for VistaPrint Coupon Codes before completing your order as there is always always a 50% Off sale running somewhere.
PSPrint: great quality, recommended quantity 500+