So if I take in our damaged device what will they be able to get it fixed and how much will that cost?

I recently dropped my ipod touch 4th gen in water, It was in the water for less than 5 seconds, but I still went through the process of drying it out that i found online. Now a day later my power button is not responding. So is there some solution or should I take it straight to the Apple store? And what will I have to pay?

I suppose it is possible to go with out a power button but i would rather not so I would really appreciate any help I can get Thank you