Thanks for the very lively and interesting discussion. The OP e-mailed a few days ago asking for the source code for DosBox Turbo. I informed him that I make available the source code to my users whom I've distributed a binary to and that the GPL specifically allows for this. I also make available the source code to the upsteam DosBox devs, and forwarded them copies not too long ago. Furthermore, I've contacted the aDosBox devs and offered to port many of my improvements into the free aDosBox software for everyone to benefit. I've never heard back from the aDosBox devs, and I am assuming it is a dead project, as there has been no activity in over a year and no response to my messages in over 4 months.
While I respect the OP's opinion that (actual price on Google play is $3.49) is too much to pay (don't forget Google takes 30% off the top), the reality is, a majority of my time is spent providing user support, fixing bugs in various Android devices that my users have, and implementing new features and suggestions from my user-base. I've amassed a collection of no less than 8 different Android devices, so that I can reproduce a wide range of reported bugs.
The OP and I may disagree on what my time is worth; however, we did have a constructive discussion about perhaps moving to a model of charging for the value add-ons (which I currently provide for free), although, I'm not sure how easy that would be within the Google Play framework. I also suggested to him that there were numerous avenues for him to obtain a copy of the binary free of charge if price was a factor (one only has to search the various Android warez sites) and that I had no problems with him going that route.
While the OP may disagree with me, I believe that being able to charge for GPL software (and comply with the GPL) allows for development of better software with features and bug fixes that would normally never occur. Believe me, it is very time-consuming to sit around for hours answering user e-mails, or spending hours to fix hard to reproduce bugs that occur only on a specific version of Android or a specific device. Few, if any people, would do that kind of tedious work for free.