How to cash in the Barry medal in Jetpack Joyride

Yes, there is an end. 30000 meters and a wall zaps you, and that's the end.

Basic troubleshooting:

Quit the app, double tap home, hold on Jetpack Joyride, and delete it. (This will not delete the game itself; it just stops running it) and then open it again and see what happens.

Otherwise I'd say un-install and re-install; this shouldn't lose your progress if it is connected to something like Game Center.