Publishing fees:

Android - 25$ once (fixed*)
Microsoft Store - 19$ once¹
Steam Game - 100$ / game²
itch.io - free²
Unreal - free⁴
Unity - free⁵

And then there is Apple...
Apple - 99$ / year

¹ (99$ for enterprise)
² (legacy was 100$ once for charity)
³ (30% of profit for them)
⁴ (5% if more profit than 12.000$/year)
⁵ (until more profit than $100.000/year)

So I came from the Portal modding scene. And I know most other ones who did similar stuff.
Now there was a cool looking upcoming free mod and I somehow came in touch with the lead Dev. Now somehow I managed to get into the developer team and me and my girlfriend we're part of it. We got a level name and should start mapping it (TL;DR, we never finished one because we didn't know what to do).

I actually made a website for the mod. But sometime later we both left the team because the lead Dev (12 yo btw) was "hiring" (working for passion not money btw, that's fine in this case) everyone he got in touch with. They had no team structure just a huge list of people and a long story script. I'd guess the mod won't ever be done, although it has made it through steam greenlight (R.I.P greenlight). Just because they're not working on a team.