Not a list of free tiers. A stack that survives when the free tiers change, the keys get revoked, and the account gets flagged — which they will.
The brain is free, and always was
Ollama, running locally. localhost:11434 — no key, no account. There is no auth header on that API, so there's nothing to leak, expire, or revoke. A small model like llama3.2 runs on an ordinary desktop and handles classification, extraction, summarization, and first-draft copy. This is your floor, and the floor never drops out.
When local is too slow, reach for free hosted tiers: Cerebras (fast, generous free allowance), OpenRouter (one endpoint over many models, several of them free), and Hugging Face (free inference plus free Spaces hosting).
The rule that makes this durable: if a component needs a key to think, there's a local version that doesn't. Use the local one as the fallback, not the last resort. Design so a dead key is a slowdown, not an outage.
The compute is free
GitHub Actions gives you 2,000 free minutes a month with cron built in — no server to rent. And your own machine is already paid for and already on; a scheduled task is just a cron job with a nicer name.
The hosting is free
Notion pages publish to the web instantly. Hugging Face Spaces hosts small apps with no card. GitHub Pages is free too — until your account gets flagged and it serves a 404 to the entire internet, which is exactly why it shouldn't be your only front door.
The till is free
A PayPal.me link is a public URL that takes money with zero credentials on your side. A Stripe payment link is a public URL that takes cards with no website behind it. You can accept money before you've built anything else.
The thing that actually kills $0 stacks
It's never the cost. It's credential leakage. You put your keys in a file so your code can read them, your automation commits that file, a scanner finds it within hours, and the providers revoke the keys automatically. Everything starts returning 401. You conclude the key is “missing,” issue a new one into the same file, and the loop runs for months.
The fix is three lines — untrack the file, ignore it, rotate the keys — then read secrets from the environment, never from a tracked file. Better still: need fewer secrets. Every key you don't have is a key that can't be revoked.
The part no stack solves
A $0 stack removes every excuse except the real one. When the brain, the compute, the hosting, and the till are all free and there's still no revenue, the missing piece was never infrastructure — it's that nobody was asked to buy. No architecture fixes that. But it's worth knowing which problem you actually have.
This is the short version. The full $0 AI Stack guide goes deeper — pay what you want, and 70% of every sale goes to the Palestinian Children's Relief Fund. Or browse everything.