Open source software already is literally free. Almost all the good stuff is developed by corporations at a pretty high price, but it's still not much considering billions of users.

Hosting apparently costs so little to provide that just a few ad clicks and some data collection, or a donation model like Wikipedia, can be way more than enough.

Some of it appears to even be given away just as a promotion.

It's not literally free, but it's getting close to irrelevant costs per megabyte of data.