This forest is held up by many small fires. Anyone can self-host a Cinderous relay node — a relay only forwards ciphertext; it sees neither your message content nor who talks to whom.
Two ways: a Cloudflare Worker (free tier is enough) or a container (Docker, self-hosted on a VPS / Raspberry Pi). See the self-hosting docs for steps.
Deploy the relay/ Worker to Cloudflare (free tier), wrangler deploy.
Self-host node-relay as a container on a VPS / Raspberry Pi (ADR-0075).
Self-report GitHub Sponsors / BMC / Liberapay / Lightning in NIP-11 (ADR-0089).
Running it makes it a working relay. To be picked up by the auto-assigned public pool, a maintainer must add it to the signed relay list (to prevent freeloading/phishing). Until then, your node is still usable by anyone who enters its URL manually, or by contacts who set it as their home (they learn the route automatically).
You can self-report donation links in your node's NIP-11 info (GitHub Sponsors / Buy Me a Coffee / Liberapay / Lightning); the desktop app shows a low-key “Support this node” card — pure external links, the app never touches money (ADR-0089).