Email marketing is the friend of zero budget marketers. It's fast, effective - and extremely inexpensive once you've built up your opt in list.
But you need to keep working on it, even more so now that anti-spam filters are getting more prevalent. It's just too frustrating to have your email blocked by someone who's actually requested it.
So make the effort to run your email through a SPAM checking service, like ezinecheck.com. It will let you know the "spam score" of your email and a few quick changes can be the difference between your mail getting through or it hitting the virtual bin!