Best AI Legal Research Stack Under $100/Mo

Westlaw and Lexis charge solo practitioners $250–$400/month for research tools that assume you bill like a BigLaw associate. You don’t have to pay that. A mix of free bar association access, a $65/month CARA AI subscription, and two $20/month AI models covers most of what a solo actually needs — if you wire them together correctly.

This comparison is for the solo practitioner or two-attorney firm billing real cases in real practice areas — family law, criminal defense, personal injury, estate planning, general civil litigation — who cannot justify a $300/month research subscription that assumes you have a paralegal, a law library budget, and a managing partner signing off on overhead. The question here is specific: can you get to 80% of Westlaw’s research utility for under $100/month? The answer is yes, with caveats worth knowing before you cancel anything.

How We Compared Them

Each tool was evaluated on four criteria: coverage (jurisdictional depth and currency of case law), AI utility (does the AI layer actually save time or just add noise), workflow fit for a solo (how fast can you go from a research question to a usable answer), and honest pricing (what you actually pay, not the introductory rate). Tools that require an enterprise call to get pricing are excluded — a solo shouldn’t have to negotiate a contract to do legal research.

Fastcase — Your Bar Association Probably Pays for This Already

Fastcase is available free through over 40 state bar associations and the American Bar Association. If you haven’t checked whether your bar dues already cover it, stop reading and check right now. For most solos, this is the single best move in legal research cost reduction.

The database covers all 50 states, federal courts, and includes an AI-assisted search tool called Fastcase AI Sandbox that launched in 2023. The AI Sandbox lets you ask a plain-language research question and get a summary with citations — not a hallucinated list, but citations pulled from Fastcase’s own verified database. That’s an important distinction. The summaries are modest: they won’t replace reading the opinion, but they will tell you whether a line of cases exists before you spend an hour chasing it.

Where Fastcase falls short: secondary sources. If you need a treatise, a practice guide, or a law review article, Fastcase’s coverage is thin compared to Westlaw or Lexis. The citator — Authority Check — works but isn’t as fast or as granular as KeyCite. I’ve hit situations where Authority Check showed a case as good law and a Westlaw check revealed a narrowing treatment I needed to know about. Not common, but worth verifying on anything you’re about to cite in a brief.

For a solo doing state-court litigation, Fastcase handles the primary law research well. For transactional work where you’re leaning on secondary sources, it shows its limits quickly.

Pricing: Free through most bar associations. Standalone access runs $99/month — skip that version entirely if you have bar access. The bar-access version is the same database.

Casetext CARA AI — The $65/Month Workhorse

Casetext was acquired by Thomson Reuters in 2023, which raised legitimate concerns about whether it would eventually be folded into Westlaw’s pricing structure. As of this writing, standalone Casetext subscriptions still exist at $65/month for the Pro plan, and CARA AI — the document-upload research feature — is still the most practically useful AI research tool in this price range.

CARA works like this: you upload a brief, a complaint, or a memo, and CARA surfaces relevant cases you may have missed — cross-referenced against what you’ve already cited and what’s missing. For a solo writing a brief at 10 PM without a research associate, that’s genuinely useful. It has caught cases I didn’t find in my initial Fastcase search, particularly in federal circuits where I don’t practice regularly.

The underlying database is solid — full federal and state coverage, CoCounsel (the AI layer Thomson Reuters added post-acquisition) is available on some tiers for drafting assistance. The citator is reliable. Search quality is good, though not at Westlaw’s level for obscure or older cases.

Where it breaks: the CoCounsel features at the $65 tier are limited. You get CARA uploads and research, but the full AI drafting workflow — contract review, deposition prep summaries — lives at higher price points. Also, Thomson Reuters has been migrating features between tiers post-acquisition, and what’s included in each plan has shifted. Before you subscribe, confirm exactly which AI features are live on the plan you’re buying. The sales page language has not always matched what’s actually accessible in the product.

For a solo doing civil litigation or appellate work, Casetext at $65/month is the single highest-value paid tool in this comparison. It earns its price on brief-writing alone.

Pricing: Pro plan at approximately $65/month. Verify current pricing directly — it has changed since the Thomson Reuters acquisition and may change again.

Justia — Free and More Useful Than Its Reputation Suggests

Justia is free, and most lawyers treat it as a last resort. That’s an overcorrection. Justia’s federal case law coverage — Supreme Court, all federal circuits, federal district courts — is genuinely good and current. State case law coverage varies: California, Texas, New York, and Florida are solid; smaller states are spottier.

There is no AI layer on Justia. No citator worth relying on for final cite-checks. No secondary sources. But as a fast lookup tool for a citation you already have, or for a quick scan of whether federal circuit precedent exists on a narrow point, it works. It’s also the fastest way to pull a SCOTUS opinion text when you need to paste it into a model for summarization.

The highest-value Justia feature for solos is the docket search. Federal district court dockets are searchable without a PACER account, and Justia often has the underlying documents for recent high-profile cases. This pairs well with PACER for matters where you need documents that Justia hasn’t indexed.

Don’t rely on Justia for anything you’re about to cite without running it through a citator. The site itself says this clearly. Use it for orientation and initial retrieval, then verify.

Pricing: Free. No account required for most searches.

Close-up detail shot of hands resting on a laptop keyboard, a printed document visible at the edge of frame rendered as

Perplexity Pro — $20/Month for Sourced Web Research

Perplexity Pro ($20/month) is not a legal research tool. It is a sourced web research tool that happens to be more useful for legal background research than most lawyers realize — and is completely distinct from what Fastcase or Casetext do.

Where Perplexity fits: you need to understand a regulatory framework before you start case law research. You’re researching an industry your client operates in and you don’t know it. You want a quick synthesis of what federal agencies have published on a topic. You need to find a law review article or a bar journal piece you vaguely remember. Perplexity surfaces sources, cites them inline, and lets you click through to verify. That verification step matters — treat every Perplexity answer as a starting point, not a finish line.

Where it breaks for legal research: it does not have access to a verified legal database. It will pull cases from Justia, Google Scholar, or whatever is publicly indexed, and it has hallucinated citations in my testing when the underlying public sources were thin. On any specific case citation, verify it independently before it goes anywhere near a brief. Perplexity is strong on “what does this statute generally do” and weak on “is this case still good law.”

The Pro tier ($20/month) adds access to GPT-4o and Claude 3.5 Sonnet as selectable models inside Perplexity, plus higher query limits. For a solo using this as background research alongside a primary legal database, Pro is worth the $20.

Pricing: Free tier available. Pro is $20/month.

Claude Pro — $20/Month for Summarization and Memo Drafting

Claude Pro (Anthropic, $20/month) is not a research tool. It does not have a legal database. It does not cite check. What it does extremely well is read a document you give it and summarize, synthesize, or draft from that document accurately — and for a solo, that’s worth $20/month on its own.

The workflow that pays off: pull your cases from Fastcase or Casetext, paste the relevant opinion text or your own case notes into Claude, and ask it to draft a summary of the rule, synthesize how three cases treat a standard, or produce a first-draft argument section you’ll then revise. Claude handles long documents better than most models at this price point — the 200,000 token context window on Claude 3.5 Sonnet means you can paste a lengthy opinion or a stack of depositions without it losing the thread.

Where Claude breaks for legal work: it will confidently produce case citations that don’t exist if you ask it to research rather than synthesize. The rule is firm — give Claude the source material, don’t ask Claude to find it. It’s a drafting and synthesis layer, not a retrieval layer. Treat it accordingly and it’s reliable. Ask it to “find cases about X” and you will get plausible-sounding fiction some percentage of the time.

Claude also works as a plain-language explainer for a client memo — paste in the legal standard and ask for a plain-language version your client can read. That alone saves 30 minutes per matter for solos who are writing client communication themselves.

Pricing: Free tier available with usage limits. Claude Pro is $20/month. Claude.ai is the consumer product; API access is billed separately and costs more for heavy use.

PACER — Not Free, But Close Enough

PACER (Public Access to Court Electronic Records) charges $0.10 per page, capped at $3.00 per document. Quarterly fees under $30 are waived entirely. For a solo doing occasional federal work, the realistic annual cost is $0 to $50. That is not a meaningful budget item.

PACER gives you direct access to federal district court, circuit court, and bankruptcy court dockets and filings. For any matter with a federal dimension, it’s the authoritative source. The interface is functional in the way that government software from 2004 is functional — it works, it’s not pleasant, and you will need about twenty minutes to learn the quirks before it stops fighting you.

CourtListener (Free Law Project) indexes PACER documents and makes many of them searchable for free. If a document has been downloaded by anyone through CourtListener, you can access it without a PACER charge. For common filings in well-watched cases, CourtListener often has what you need before you open PACER.

Pricing: $0.10/page, waived if quarterly charges are under $30. Free Law Project’s CourtListener is free and covers a substantial portion of PACER content.

Side-by-Side

Fastcase (free via bar): Primary law — strong. AI layer — modest but cited. Secondary sources — weak. Citator — adequate, verify critical cites elsewhere. Cost: $0.
Casetext CARA AI ($65/mo): Primary law — strong. AI layer — strong for brief-writing and gap analysis. Secondary sources — moderate. Citator — reliable. Cost: $65/month.
Justia (free): Federal primary law — good. State — varies. AI layer — none. Citator — do not rely on it. Cost: $0.
Perplexity Pro ($20/mo): Background and regulatory research — strong. Case law retrieval — unreliable, verify everything. Citation checking — do not use for this. Cost: $20/month.
Claude Pro ($20/mo): Summarization and drafting from provided documents — strong. Independent case retrieval — do not use for this. Long-document handling — best in class at this price. Cost: $20/month.
PACER (~$0–$50/year): Federal dockets and filings — authoritative. No AI layer. Cost: near zero for most solos.

Total at maximum spend: Casetext ($65) + Perplexity Pro ($20) + Claude Pro ($20) = $105/month. Drop Perplexity if your research is purely case-law-driven and you hit $85. If your bar covers Fastcase, drop Casetext for lighter research matters and you’re at $40/month.

Picking the Right One

If you do state-court litigation and your bar covers Fastcase: Start there. Add Claude Pro ($20/month) to summarize opinions and draft argument sections. That’s $20/month total and covers a solid majority of research needs for standard civil or family law matters. Add Casetext if you’re writing federal briefs regularly or if you want the CARA gap-analysis feature on your brief drafts.

If you do federal practice — civil rights, immigration, bankruptcy, securities: Casetext at $65/month is the core tool. Add Claude Pro for document synthesis. PACER for dockets. That’s $85/month and you have a genuinely capable research setup for federal work.

If you handle matters with heavy regulatory or administrative law components: Add Perplexity Pro ($20/month) to the above. Perplexity’s ability to synthesize agency guidance, Federal Register notices, and secondary commentary in one sourced answer is real. Just treat every output as a lead, not a conclusion.

If you need secondary sources regularly — treatises, Restatements, practice guides — this stack has a genuine gap. Fastcase’s secondary coverage is thin. Casetext has some secondary content but not at Westlaw’s depth. If secondary sources are load-bearing in your practice, consider whether a low-volume Westlaw Essentials plan ($69/month as of this writing, though pricing varies) covers that gap more efficiently than any combination here. That’s a different calculation, not a failure of the stack above.

What this stack does not replace: Westlaw’s KeyCite for critical cite-checking on anything you’re submitting to a court. If you’re on this stack and you’re about to file a brief, run your key citations through Fastcase’s Authority Check and cross-reference at least a sample through a free Westlaw trial or a colleague’s access. The cost of one bad cite in a brief is higher than any monthly subscription.

The combination of Fastcase (free), Casetext ($65), Claude Pro ($20), and PACER (near zero) gives a solo practitioner a research workflow that is meaningfully faster than manual research and costs less than a single hour of BigLaw billing. That’s not a compromise — it’s a competent, honest toolkit for the way solos actually work.

The Best AI Legal Research Stack Under $100/Month for Solos