btw for the record i think that 30% is way way too high, and is the kind of mark up that you could only get away with by having a near-monopoly control over access by consumers.
-mouser
Yes and no. 30% isn't too high if the store is doing some work. The iTunes store does exactly zero work -- it adds zero relative value. It's the ONLY option for consumers. If anything, as pointed out above, it acts to the detriment of consumers. Good software doesn't rise to the top --- good SELLING software rises to the top. i.e. You are charged 30% for the 'privilege' of being admitted to the store. Freeware is admitted because if they didn't, consumers wouldn't buy the iPhone at all.
If someone goes out and gets customers, then 30% is fair, and even low sometimes. The app store doesn't do that. It robs you of 30% for sending you to the bottom of the LOOOOONNNNNGGGG list and scraping 30% off the sales to the 3 people that find you...
For percentages, think of it this way --- I will give anyone out there a 50% commission on sales for getting me customers that I would not otherwise get. It's good for me and you. After all, 100% of nothing (customers that I would not get otherwise) is nothing, where 50% is something.
For other software, 3% could be "high".
There have been cases of paying for customers for freeware, and they have added value.
It's a VERY broad topic, and I think each case needs to be evaluated on its own.
My $0.02 anyways.