As someone who is under-employed or unemployed, your marketing budget is very much like a non-profit; little or nothing.
Does that stop the non-profit from marketing themselves? No, nor should it stop you.
Social media tools have a great entry point for both non-profits and the unemployed - most of them are free! With zero dollars down, the ROI (investment in this case) can be positive.
Listen to John Haydon talk about other ways to think of ROI in this brief (3 minutes or so) video.
John Haydon, Inbound Zombie from What Gives on Vimeo.
How can you use that info to help your job search?
How do you use your LinkedIn profile to create interest?
How do you use your activity in a LinkedIn group to create influence?
If you like this video of John, he has more advice for non-profits on his website that you can re-purpose for your job search. http://www.johnhaydon.com/
If you would like to to explore this further before you start 'mud wrestling' don't hesitate to ask me.