I've probably mentioned this before, but VistaPrint is a GREAT site for any of your promotional goodies. I've used them for bookmarks, signs, postcards, and more. Great quality and really good prices - even better since they usually email you discounts after you've ordered from them. Check it out if you haven't yet!
Always take advantage of the chance to guest blog or do interviews at the various writer-reader websites out there. Many of those are free, and all you have to do is contact the site or blog owner. If you belong to (or join) a discussion group/loop, you'll often know about opportunities before the general reading & writing public, too. There are sites that will set up these kinds of blogging/online appearances for you, too, but they often charge, so keep your eyes open for FREE chances as well.
Finally, don't underestimate the power of making personal connections with potential readers. There are so many ways to do this, from responding to comments on a social media site, to taking advantage of in-person meetings, book signings or conferences etc., to joining a writers' or reviewers' group to donating your books to giveaways or auctions. People love connecting with writers - people love connecting with others in general, since we're social creatures - so take advantage of it!
Bottom line: there are many, many inexpensive, or free ways of promoting your name. And oftne, all it takes is a little time. Good luck!