Can I return music purchased on iTunes ?

Nope. Sadly once you've purchased it's yours forever. Unless you delet it and completely wast your money.

P.S. I'm not completely sure so just wait for other responses.

As Meg said, the terms of sale for the iTunes Store state that all sales are final, so there's probably nothing to be done other than to purchase the other album if you want it. You can contact the iTunes Store, explain the reason for your request, and ask, though:

http://www.apple.com/support/itunes/contact.html

It's possible they'll make an exception for you. Certainly there's no harm in asking.

Good luck.

Yes of course you can. I once bought songs on iTunes by mistake and contacted them at support. They returned my money!

My son purchased an incorrect album once and iTunes support refunded the money and deleted the album from our iTunes. They representative said that it would be a "one time" courtesy. Therefore, I would assume that multiple requests for refunds would result in the request not being granted.

All sales are final.

You sure can - http://www.youtube.com/watch?v=siPw8ZPgsBE

Thanks for posting such a straight forward guide to iTunes refunds.