Sign up at Mr. Rebates and get a $5.00 registration bonus. Then you can find the store you want to purchase from (ex. iTunes) and get a % back. They have over 2000 stores.
At ITunes you will get 5% back plus the $5 bonus if your new.
Once your account hits $10 you can request a check. It's another site that pays you for your normal purchases online. Nice!
Shop At Home has 4% for iTunes
Ebates has 3% for iTunes