Ipod touch screen replacement

I bought a new ipod touch screen off amazon because i cracked the original screen. The screen is a perfect match.
I went to an apple store and they said that screen repair would cost over £80. I thought this was a rip off as buying a screen online costs only £20. I don't want to replace it myself because theres a chance i might destroy it completely and cost even more to replace.
Will the apple store fix it if i give them the screen i bought and my broken ipod?

If you didn't want to do it yourself or have a shop that would do it for you, you probably should have just let them do it to begin with. If they will replace it with your screen, you're not likely to get a discount equivalent to what you paid for the screen from their original quote.

The only way you'll know for sure though will be to ring them up or drop by the store. There are no Apple employees here, or at least none that could address Apple policy with a definitive "take it to the bank" answer.

Look it up on You Tube, there are some quite good videos.