4. The three cost layers
From the Meridians Wiki · Public · Maintained · joint
| Layer | What | ~$/mo | Scales with |
|---|---|---|---|
| Fixed per instance | Fly machine + volume + (self-host) ngrok | $6–8 | # of instances (1 per managed tenant; rooms share) |
| Marginal per seat | Stripe fees (Telegram delivery is free) | ~$1.00 | # of paid seats |
| Per-seat usage | LLM + embeddings + images + crawl + TTS | $0.50–8 | how hard the seat is worked |
Infra amortizes across a room (one box, many seats); the usage layer is the only one that's genuinely per-person-variable — and the only one a flat price misprices. Token-based pricing is precisely a meter on layer 3.