The cheapest AI stack in 2026 isn’t one provider’s free tier — it’s several, running side by side. Done right, that’s completely legitimate. Done wrong, it’s the fastest way to lose every account you have. Here’s the line, drawn precisely.
The principle: stack horizontally, never vertically
Horizontal stacking — one account with each of many providers — is ordinary multi-vendor engineering. Nothing in any provider’s terms forbids you from holding keys at Google, Groq and Cohere simultaneously; they meter you independently.
Vertical stacking — multiple accounts at the same provider to reset a quota, fake eligibility for a program, or cycle payment cards through trials — violates terms of service. Beyond bans, it poisons the well: providers that see abuse tighten or kill the free tiers everyone else relies on. This site never lists offers that require it.
A worked example: the $0 stack
All six of these run in parallel today, each within its own published terms (verified figures on each offer page):
- Gemini API free tier — daily driver for a capable general model, on the models Google marks free.
- Groq — fast open-model inference (per-model published limits, e.g. 30 req/min and 200K tokens/day on gpt-oss-120b).
- OpenRouter — 50 requests/day across a rotating ‘:free’ catalogue, for model variety and fallbacks.
- Cloudflare Workers AI — 10,000 Neurons/day if you’re deploying at the edge anyway.
- Mistral Free mode — Mistral’s own models, on the default plan for new accounts.
- Cohere trial keys — the embeddings and rerank lane, 1,000 calls/month.
OpenRouter, Cloudflare and Mistral say in their own words that no card is needed; Google, Groq and Cohere don’t say either way. Hugging Face’s monthly credit used to fill a seventh slot; its docs have listed none for free accounts since 7 October 2026.
Route each workload to the tier whose limits fit it, and use a library-level fallback chain so a 429 at one provider fails over to another — the rate-limits guide covers the mechanics.
Adding one-off budget on top
When a free tier can’t cover a burst (a batch job, an eval run), add one cloud trial you haven’t used: Google Cloud’s $300 / 90 days, AWS’s up-to-$200 / 6 months or Azure’s $200 / 30 days. Each is a “new customers of this cloud” program — being an AWS customer doesn’t affect your eligibility at Google, and none auto-charges when the trial ends. If you’re a startup, the startup programs stack on top of all of this.
What crosses the line (don’t)
- Multiple accounts on one provider to reset daily/monthly quotas.
- Fake eligibility: claiming a founding date, funding round or student status you don’t have. Programs verify, and revocation is retroactive.
- Card or identity cycling to re-enter “new customer” trials on the same cloud.
- Terms-dodging automation, like distributing one workload across farmed keys.
The legitimate stack above is generous enough that abuse isn’t just risky — it’s unnecessary. For current numbers across everything, start at the directory.