Normally Apple takes 30% of any money taken through the Apple store. Oceanic will be an early adopter, having several months and almo certainly Apple's support in return for testing an Alpha developer and being NDA'd up to their eyeballs.I am not so sure, one must take into consideration that the deal is with Apple and Apple sets the rules and terms. If anyone that can be thought of as greedy, Apple is the first suspect not Oceanic. We don't know the terms and conditions set by Apple for Oceanic but I am sure that it isn't soft or easy.
Will be little or nothing stopping other developers from building similar applications, patents and legal crap aside.