So version 0.3 and further is not free?
Kind of. So, to download the game, you will need to pay $3. You will then own it for future updates as long as the game stays $3 (which, the only way I'd increase the price would be when the game is actually done, but that'll be a while).
With that said, the version of the game that plays in the browser is the latest version, and it will always be the latest version as long as I have the power to do so. So you can play the latest version, for free, by just playing the game in the browser.