If I come across a productivity app that allows me to test it's full functionality or at least the majority of it and the results are what I expect and the app fulfills a need of some type then I'll pay a reasonable price for the app. One example is Wyse Pocket Cloud (a remote desktop app). I was able to test the majority of the functionality via a free version-it worked well, met most of my needs for a RDP app. The paid version provided additional functions that also worked well so I had no problem paying for the full app.