The normal home and back buttons of any Android device are replaced by virtual buttons on screen. You can see the buttons in the lower left-hand corner of the screen.
Nobody wants to spend money on something that isn’t useful. It doesn’t matter whether you’re spending one, five or a hundred dollars. Of course, there are simply some applications that are just not as good as the trial or free versions. It can be difficult to figure out which of the paid android apps are most worth the money.