Why is this free?

Lute is and will always remain free for a few reasons.

1. Reciprocity. When I've studied languages, I've had the great benefit of finding top-notch free technology and content from many, many people and organizations.

2. Freedom from accountability! Yep, I said that. While I would appreciate any kind of voluntary donation you might wish to give me for making Lute, I can't ask for payment. Lute is open source software, and as such will always be a work-in-progress, no matter how great it is. Requiring payment for use would create an additional burden of responsibility towards each user, and potentially cause frustration for users who buy something that doesn't quite work for them.

3. Anki does it, why can't Lute? Anki is miraculously free. They have a great system, central server syncing, a massive community ... it's something to aspire to.

Who knows, maybe at some point Lute will become financially rewarding. That would be a happy accident, but that's not the main goal.