What I found as I started this search was really interesting. There are many free survey apps that pay you to fill out their ready made surveys. While I haven't found a gold mine (it's $0.05-$0.25 a survey) in just this research I racked up earnings of about $1.45!
My first finding is that all of these apps only ask one question per page. The surveys contained anywhere from 4-20 questions, and each had a different way for the user to proceed.
Sorry for the stream of conscious but there is one last point I want to highlight. All of these apps showed consistency. The layout of each page was the same and there was therefore no need to re-orient once moving through the app. I have been playing with a lot of different designs for IBDPromise and I will have to settle on one template design for all the questions that will exits continuously throughout the app.