I should clarify: Among people that don't use credit cards like kids or the paranoid, the typical solution is to use a gift card. I, personally, do not like to use credit cards for purchases less than 40$. I certainly didn't think my comment was worthy of downvoting, especially since the comment I replied to asked if it was required.
https://news.ycombinator.com/item?id=10231933
so you won't have to wait terribly long. And there are already a few that have IAP but basic functionality is free.