I have been writing a program on & off for the past few months that would be of interest to around 10-15% of internet users (very general subject) but it's not likely to sell if I tried to due to a few features that are impossible to automate without upsetting a LOT of my target market. Due to this I have removed some of the main features (the upsetting parts) & it has massively reduced the functionality / automation of the program so it would be very difficult to ask for payment before use, especially as a startup anyway so I am looking at having advertisements inside of the software instead of payment to profit from its release. CPA offers would work well with the software but I would also like to know of any other sources of income that anyone has had from adding advertisements into your own software, the obvious parts being: Ads / Ad-Free Version At A Cost; CPA Banner Advertisments / Promoting your own sites or products; Token / Credit systems can work but not with my software; PPC - Is this available for software developers? Email Advertising once those have registered to use the software. Has anyone tried any of the above / other ideas & willing to share your results?