Hi,
The individual is permitted to make up to $5,000 USD lifetime revenue (or equivalent in other currencies/payments/benefits) from their creations. This includes but is not limited to revenue generated through advertisments, in app purchases, sale of content, licensing of content, contract work.
If you generate more than the above stated revenue you must upgrade your Personal Edition License into a Business Edition license within 14 days regardless of if you intend to continue use of your license or not.
http://www.scirra.com/store/licensing#license2