I disagree wholeheartedly. Make money now. Don't leave it on the table. Sell 50,000 (or 100k! or 200k!) copies at $3 or $5, and then approach sheet music copyright holders.

Copy the business model that Tapulous uses for Tap Tap Revenge: I should be able to download a Ben Folds-branded copy of Etude, and then a separate Beethoven app, and then a separate Liszt app. Each one should cost five bucks. And then user should be able to buy EVEN MORE CONTENT via in-app purchases.

Showing content owners that you've already made a million dollars (or whatever) is much more compelling than vague hand-waving about market share and potential of an installed user base.

I get really frustrated with this notion that newly released software should be free, or that monetization potential is always increased by giving something away. Who knows what might happen tomorrow?

Perhaps an app significantly better than Etude will soon be released. Maybe Dan Grover will get bored of working on Etude. It's possible that sheet music copyright holders could even be dumber than music labels, and they'll be unwilling to cut a deal.

There's money to be made, and the best way to make it in the short term is to sell the app.