Amex has released a very nice new targeted offer for Itunes. The offer which expires 8/31/2015 gives a $5 statement credit on a purchase of $5 or more. (Some people have reported receiving an offer for $10 off $10 as well.) Unfortunately this Amex Offer appears to only be available via the American Express website and cannot be loaded via Twitter or other methods.
While the offer is targeted, it appears to be pretty widely available for personal cards. I received it on 7 out of my family’s 8 personal cards, but on 0 out of our 4 business cards. (Update: It may be more restrictive than I originally thought based on the comments.)
Offer valid only for iTunes, App Store, and iBooks Store purchases made through iTunes. iTunes gift cards purchased in Apple stores, on Apple.com, or through a 3rd party are excluded. Not valid for purchases of any other Apple products in-store or online at Apple.com. Must add offer to Card and use same Card for one or more transactions in order to redeem. Enrolled Card must be set as iTunes payment method in order to receive statement credit. If you receive a replacement Card during the offer and use that Card to enroll, you must update your Card on file with iTunes prior to your purchase to receive the statement credit.
For more information see: The complete guide to Amex Offers