🔎 Free options · limits checked Oct 18, 2026
Free AI tools to research
Short answer: start with Perplexity on its free plan. We found 6 tools for this job with a free tier we verified in the last 30 days.
Every free option, with the catch
| Tool | Free tier, as listed | The catch | Paid from | Last checked |
|---|---|---|---|---|
| Perplexity Top pick | Yes | Limits not published in detail; check the vendor's page | $17/mo Pro billed annually | |
| Gemini (Deep Research) | Yes | Limits not published in detail; check the vendor's page | $4.99/mo Google AI Plus; $19.99/mo AI Pro | |
| NotebookLM | Yes (up to 50 sources per notebook) | Limits not published in detail; check the vendor's page | $4.99/mo via Google AI Plus | |
| Google AI Studio | Yes | Limits not published in detail; check the vendor's page | Free tier; Argon API $2/$10 per 1M tokens thru Nov 30, then $4/$20 | |
| Google Deep Review | Yes (2 reviews/week) | Usage caps reset on a schedule; heavy use needs a paid plan | Gemini API pay-as-you-go beyond free | |
| Exa | Yes ($10 credits/mo) | Usage caps reset on a schedule; heavy use needs a paid plan | Pay-as-you-go from $4/1k Instant searches |
When it's worth paying
Upgrade when you hit the free limits every week, or when you need commercial rights. The cheapest verified paid plans for this job right now: Google AI Studio from Free tier; Argon API $2/$10 per 1M tokens thru Nov 30, then $4/$20; Exa from Pay-as-you-go from $4/1k Instant searches; Gemini (Deep Research) from $4.99/mo Google AI Plus; $19.99/mo AI Pro.
See the full comparison, paid tools included: best AI tools to research.
How we check: every price and free tier on this page comes from the vendor's own pricing page, with the date we checked it. If we can't verify something, we say so. Found a wrong price? Email info@usethissi.com and we fix it within 24 hours.