Clash of Clans for example, there are tons of videos and more being made about 'gemming' their townhall in just a few minutes. Since the new update, it may cost over $200.
I don't know of many apps, just the basic kind that are on your phone when bought, and a few games, but it is probably too much money spent.
People used to spend money to buy the best apps, but now most apps are free. Sure, microtransactions are still in the games, but I don't know a lot of people who actually spend money and you can earn in game credit by watching ads. Kids especially don't, because they have to use their parent's credit card, or purchase a card to redeem virtual cash. Sure, kids do spend too much money on in game credits sometimes, but it's no big problem.