There are a few common scams that directly demand Google Play or iTunes gift cards from the victim. The most depressing one I've heard about is a phone scam where the caller claims to be from the IRS and demands that the victim pay some overdue taxes in the form of gift cards. This is common enough that I've seen notices specifically warning about it on the gift-card displays at drug stores. The fact that this scheme apparently works says a lot about America's civics education.