What is the best way to attract members to a political forum without spending a fortune on advertising?

[adkenar]

I've recently started a political forum based on the rational debate of political issues in search of the best solution. I'm paying for everything out of my own pockets, which, being a college student, are not exactly overflowing with cash. I've established a good bit of discussion with some friends, who are active. I've tried google advertising, I've tried starting a group at the university here, I've tried putting up signs, I've tried getting my friends to spread the word amongst their friends, but I just can't seem to motivate other people to get involved.