I researched this once a while back. As far as I know, I could ship the game using free, but a lot of cosmetic options would be locked. The Unity splash screen for example. It makes a professional look impossible. The rest of the limitations don’t really apply to my project.
Never fear though, Unity is available for $75 per month. So, I can start a subscription toward the end of development, polish it before release if I want, and buy a license when the amazing profits start rolling in.
Voxel planet engine mark II is coming along. Pics forthcoming. Keep the faith.