my 2nd generation ipod touch won't turn on?

hey, so my 2nd generation ipod touch is about 2 years old and it wont start. it was kinda broken a few months ago because i dropped it a lot of times and it has 2 dents in it. then after a few months my baby sister kept taking it when i wasnt looking and she would throw it across the room. then my ipod would lock randomly by itself. i wouldnt even press anthing. it did it more often then and it would randomly lock like every 30 seconds and i would have to type in my password like every 30 seconds and it would make the click noise too whenever it would lock. then my sister took it again when i wasnt there and she did osmehting with it. when i found it the screen was white and then it drained to black. i tried turning it on but it wouldnt start. i tried charging it too but that didnt work and i held the home button and the sleep button at the same time for 10 seconds but it didnt work. does that mean my ipod is dead like i have to buy a new one or can i go get it fixed at an apple store ? and how much does it cost to get it fixed?