Hot answers tagged hci
The economic concept of marginalism comes to mind. Actors will spend money to buy virtual goods if the marginal cost (price) is lower than the marginal (subjective) utility of the virtual good. If you have lots of money it's easier to spend $10 on extra lives. This explains some of it. Most of the purchases are small, so the individual cost/utility analysis ...
Only top voted, non community-wiki answers of a minimum length are eligible