Biased answer since I work on Unleash, but the pricing point is something we thought about deliberately:

- Self-hosted open source is free, with no usage limits. Run it on your own Postgres and you pay for a small VM.

- Paid plans are priced per seat (people using the admin UI), not per end user or per request. One million MAUs or a hundred million costs the same (we have some protection for high traffic volumes)

- Server-side SDKs evaluate locally, so a flag check never hits our servers and there's nothing to meter. Frontend traffic goes through Edge, which you can also self-host.

If you'd rather not lock into any vendor, put flags behind OpenFeature. Unleash, Flagsmith, GrowthBook and others all have providers, so switching later is a config change, not a rewrite.