How a builder grew a SaaS to $13K/month with free tools marketing

Executive overview

Most founders who hate marketing default to paid ads or cold outreach — both painful for builders. Bhanu built SiteGPT to $13K MRR without spending a dollar on marketing by treating tool-building as the marketing channel itself.

He built ~50 small free tools, each targeting a low-competition keyword. Together they drive 50,000 monthly visitors, 90% from Google.

Build free tools that rank for low-difficulty keywords and funnel visitors to your paid product.

What SiteGPT is and how it converts

• AI chatbot for your website — trained on your own business content
• $100 average revenue per customer, ~130 business customers
• 50,000 monthly visitors → 200 leads → 60 trials → 25–40% convert to customers
• Customer lifetime value: ~$1,700–$1,800
• No paid marketing — 60–70% of traffic from Google, almost all from free tools

The seven-step free tools playbook

1. Open Ahrefs Keywords Explorer with a blank search to surface all keyword data.
2. Apply an "include" filter for terms relevant to your product category (e.g. "AI", "generator").
3. Set keyword difficulty (KD) filter to 10 or below — keywords any decent site can rank for.
4. Set minimum monthly search volume to 1,000 to filter out negligible traffic.
5. List qualifying keywords in Notion with volume, KD, and relevance to your main product.
6. For each keyword, define the CTA that links the free tool back to your paid product.
7. Score and prioritise by: high volume + low KD + easy to build + highly relevant.

Building and scaling the tools

• Each new tool takes under five minutes to build using AI (e.g. Cursor) — prompt it to replicate an existing tool for a new keyword.
• Tools must be topically adjacent to the core product so visitors are plausible customers.
• CTA design matters: bridge the free tool's job-to-be-done to the paid product's value prop.

Stack and tools

• Ahrefs — keyword research
• Cursor / Claude Code — building free tools with AI
• SiteGPT — website support chat
• Feather — blog
• Bento — email
• PostHog / Datafast — analytics
• ChartMogul — subscription analytics
• Mintlify — docs
• Cal.com — customer calls
• Sibili — call recordings
• Featurebase — feature requests and bug reports

Founder advice

• Launch with the core feature only — don't spend months polishing before release.
• Let user feedback dictate product direction after launch.