The editor is free and the plan is to keep it that way. Building a character, compiling it and rebuilding it after every game update costs nothing and is not going behind a paywall — mods that keep working through Early Access are the whole point.
It does cost something to run, though, so here is what and how much.
Compile server
The machine that turns a character into a mod. It runs one build at a time and is the single largest cost.
$70
Web hosting
The editor itself — every page and API route.
$40
Database
Cloud saves, version history and the hub.
$40
Total each month
$150
5552
Mods built
2055
People
$0.03
Per mod built
These are counts of actions, not of people identified — the editor records that a mod was built, never what was in it. See the privacy page for exactly what is and is not stored.