but I need to start off with Android applications/games, does an app cost much to make?No, absolutely not. You can download the Android SDK including developer tools and emulator from here, which costs exactly nothing. You don't even strictly need to own an Android device.
But of course, it's still not "free" because you must invest weeks/months for learning (above all, Java programming). A game doesn't just drop from the sky. On the other hand, don't be discouraged, many people have gone that way before.
Thanks!
I think you should just try. You said you programmed C already.
You are just missing the basic knowledge about starting a game compared to some other program.
You can easily read up on what a gameloop is, that you get input, update game logic and then draw. Now start with something really simple like tic-tac-toe with character output on PC. On first try it may take a week of repeatedly gathering knowledge for an hour then writing 2 lines of code, next time it will be faster.
Thanks!