Yes that's true - in fact there are multiple strategies that can be employed when monetising an app, neatly summarised in this TechCrunch article: http://techcrunch.com/2012/08/26/how-free-apps-can-make-more...

The author seems bothered by the multitude of negative reviews and support requests generated by a cheap app. Not all of these are bad - in fact they are real-world user tests and are useful for debugging and improving the app.

I propose having a free version for those who want to try out the app, with a caveat that users who need better support and more frequent upgrades should try out the paid app instead.