How to Advertise a Facebook Application for free?

I have a couple of facebook apps that I want to advertise. The problem is if i advertise on a normal site, the link directs users to the facebook app page, which in turn redirects the users to facebook login page. I guess most ppl think its phishing attack and decide not to login.

Right now I am totally dependent on the my app users inviting their friends. So what other options do i have to market my facebook app without paying??