Render Legion, the developer of Corona Renderer, has stated that for the Alpha 6 version of Corona Renderer for 3ds Max will perpetually remain available as a free download, even though the full version of Corona Renderer 1.0 was released in February 2015. It retails for 24,99 €/month but they’re having a promo right now for 19,99 €/month. With strength of the US dollar right now, that’s not a bad deal!
The free Corona Renderer Alpha 6 was released in March, 2015. According to the website “It is a very capable render engine and we want to give it out for free to everyone who does not want or is not able to afford Corona Renderer 1.0. There is no time lock or limitation of any kind, and you can use it for both educational and commercial projects.”
Sounds pretty cool to us, but note that there will not be any bug fixes. Use it as-is.