This topic is meant to be informal about plans from Amazon:
"Android developers now have the option to be paid by the minute rather than by fees for in-app items."
http://www.informationweek.com/mobile/m ... id/1321950
"The companyâ€™s announcement states, â€œMany apps and games that are marked as â€˜freeâ€™ turn out not to be completely free. They use in-app payments to charge you for special items or to unlock features or levels. In Underground, you will find 100% free versions of popular premium titles.â€"
http://www.networkworld.com/article/297 ... -apps.html