All in-app purchases for iOS only have to be purchased once and then they will be available from all your other iOS devices running our app. After making an in-app purchase on one device you will then be able to enable the pack on your other devices by going to the “Settings” —> “In-App Purchases” (soon to be renamed “Upgrade Advisor”) and tapping on “Restore All Purchases” at the top of the screen. You must be using the same iTunes account on all your iOS devices.
The iOS in-app purchases are not available on the Mac and vice versa because Apple manages them as completely separate stores. You will have to separately purchase them.