We paid for it on my phone (which has family sharing turned on), and neither our iPad nor my wife’s iPhone can get the purchase to work. It wants us to buy it again. I regret paying for it. There are lots of flash card apps in the App Store, so it’s best to pay for one that will work on all your devices. (This is especially important when buying stuff for our baby, since my wife will not always have my phone around.) We connect it to our Apple TV, so if I’m at work, my wife can’t use the app. Now we have to pay for another flash card app. However, we will not pay for this one multiple times.