[bsaul]

But then why do you assume i've got no expenses ? Just because i'm the only one working on it doesn't mean i don't have to pay myself something to live. That's actually my point : the app doesn't generate enough revenue to cover my personnal expenses.

[scarface74]

The marginal profit is the price the good sold for - the marginal cost. The only thing Apple has to do with this is the 30%.

The only fixed cost imposed by Apple is the $100 developer fee and whatever it cost to buy a Mac.