I think there are so many ways for you to promote CPA offers in any niche for free @jazzvaga. You can start with the following:
1. Create and upload videos to Youtube and optimize it
2. Go to niche forums, build relationships and share them your CPA offer
3. Build niche targeted followers on Twitter by participating and engaging with their posts
4. Create a Blogger blog and do some on and off-page optimization
5. Participate on various niche Facebook groups, build relationships and share your CPA offer landing page
The first time I earned with CPA marketing was on a free source, which is from my Blogger blog and promoted it by writing an article and publishing it to Ezine Articles. Just my two cents.