Will they charge me at the apple store?

So I have an iPhone 4 and the lock button broke on it and now the home button is starting to go… It is still in its first year of purchase, so apparently I can go in and they will give me a new one? Or will I have I pay to get it fixed? If so how much? How long of a wait would it be, because its a 40 minute drive to the apple store and rides are limited so I would have to get it done all same day…

I'm not positive if that will fall under the warranty since its cosmetics not software. Your best bet is to first call them and ask them about warranty policies and see if you are qualified