Is there a difference between a Itunes gift card and a app gift card

Between iTunes and app gift cards no, they are redeemed onto your iTunes account and can be used in the iTunes store, app store, ibookstore and Mac App Store - there is if it's an Apple Store gift card, they can only be used in Apple's bricks-and-mortar stores and their online stores.

Message was edited by: King_Penguin

Can iTunes gift cards be redeemed at an Apple Store for product?

No, they can only be used with your iTunes account (so purchases in the iTunes Store, App Store, iBookstore and Mac App Store)