Zero Budget Marketers need to be online. But your online content needs to be dynamic, updating regularly so that your news/stories/case studies/products are always up to date.
If you don't have a website that allows you to change your own content, it can be very expensive to keep content up-to-date. Most web designers charge $80+ an hour - and very little takes less than a few hours to do.
Thus, it's not just recommended, it's essential that you have this capability if you're on a zero budget.
Today, rather than take my word for it, read this article which sums up the WHY of a content management system very nicely. (Evolt, where it's published, is an online community for web developers, so it's written from that perspective, but is still very easy to read and quite comprehensive).
In Oz, I've used a few inexpensive content management systems that I recommend to clients: www.webalive.biz (about $400 a year), www.sauceopen.com.au (around $2k set up plus $150 a month) and www.eknowhow.com.au (about $800 a year). There are literally hundreds more, these are just the Australian based ones that I've used and have been happy with, especially as the latter two include email marketing systems.
PS. Let me know if you've come across any other goodies!