What AI tools do I need for a content marketing engine?

draft content (Wordtune), optimize for search (KoalaWriter), create visuals (FLUX (Black Forest Labs)), run campaigns (Common Room). That's 4 jobs; you don't need one expensive all-in-one.

How much does an AI content marketing engine stack cost per month?

Picking the cheapest paid tool for each job, about $18/mo total. 4 of 4 jobs also have a genuinely free option, so you can start at or near $0.

Can I build a content marketing engine stack for free?

Yes — every job here has a free tier, so a fully-free stack is possible (with the usual free-tier limits).

The cheapest AI tool stack for a content marketing engine

Running a content marketing engine takes 4 AI jobs. Pick the cheapest solid tool for each and the whole stack costs about $18/mo — or as little as $0 using the 4 free options. Here's the build, with each tool's honest catch.

A content engine needs four moving parts working together: drafting at volume, optimizing each piece for search, producing supporting visuals, and distributing through ads or email. The trap is paying enterprise prices for all four. This stack assembles the cheapest credible tool per role, with free options flagged.

Job	Cheapest pick	From	Free option
Draft content	Wordtune AI Writing & Content	$7/mo	Copy.ai
Optimize for search	KoalaWriter AI SEO	$9/mo	Keyword Insights
Create visuals	FLUX (Black Forest Labs) AI Image Generation	$0.03/mo	Adobe Firefly
Run campaigns	Common Room AI Marketing & Sales	$2/mo	6sense
Total to run this stack		~$18/mo (4/4 jobs free-capable)

The honest catch on each pick

Draft content: Wordtune

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Best for: Professionals who want to rewrite and polish their own sentences for tone and clarity in real time.

Watch out: Teams needing full content production, SEO tooling, or large-scale campaign generation.

Has a free tier

Optimize for search: KoalaWriter

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Best for: Bloggers and niche-site owners who want fast, low-cost AI article drafts informed by current SERP data.

Watch out: Enterprise content teams needing deep SEO auditing, rank tracking, or brief collaboration features.

Has a free tier

Create visuals: FLUX (Black Forest Labs)

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Best for: Developers wanting cutting-edge open-weight quality with an API option for production.

Watch out: Non-technical users who want a polished consumer UI rather than models and an API.

Has a free tier

Run campaigns: Common Room

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Best for: Developer-focused SaaS companies that want to convert GitHub stars, Slack members, and contributors into pipeline.

Watch out: Traditional B2B companies without a developer community or product-led-growth motion to draw signals from.

No free tier — from $2/mo

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Frequently asked questions

What AI tools do I need for a content marketing engine?: draft content (Wordtune), optimize for search (KoalaWriter), create visuals (FLUX (Black Forest Labs)), run campaigns (Common Room). That's 4 jobs; you don't need one expensive all-in-one.
How much does an AI content marketing engine stack cost per month?: Picking the cheapest paid tool for each job, about $18/mo total. 4 of 4 jobs also have a genuinely free option, so you can start at or near $0.
Can I build a content marketing engine stack for free?: Yes — every job here has a free tier, so a fully-free stack is possible (with the usual free-tier limits).