Its all about 'VOLUME' the more traffic you gain, the more revenue your earn. Thats my motto! Its all a numbers game. You can put any shit product on the net and be certain that at least one person will buy it.
I always stick to looking at a 1% conversion rate. Although I always manage more than this but I stick with this number to keep my expectations and hopes at a minimum. For example get 100,000 impressions of your product website and you can be certain that around 1000 people will visit the site and around 10 people will prob buy it.
Just drive as much traffic as you can and some idiot will buy it. To find more idiots than anyway else or to be nice to them - people who believe the lies you state in the sales letters, pitches! Look at markets including students, school leavers (16-18yr olds), laborers and people in manual, hard working, grafting jobs, and people on benefits, living in council houses etc.
This is who I mainly target and they convert better than any other demographic and are more likely to buy what you are selling. As the saying goes 'the more older you become, the more knowledge you gain, and more wiser you become'. In the case of this target them young as they are less mature, less commitments, more money to spend and give to you.