Building an AI Sales Prospecting Stack for Under $500/Month

A reader emailed last week asking what our actual sales tech stack looks like. They were quoted $4,500/month by a vendor for an "AI-powered prospecting platform" and wanted a sanity check. Here's our complete four-tool stack that does roughly the same work for under $500/month total.

This is for a small B2B sales team (four people, ~30 qualified meetings booked per week). It will not scale to a 50-person sales org and isn't meant to.

The stack

Data layer: Clay — $149/mo for the Starter plan. Pulls in company and contact data, enriches with LinkedIn, Apollo, BuiltWith, and twenty other sources, then runs AI prompts over each row.

Research layer: Perplexity Pro API — about $40/mo for our usage. Researches each lead account before outreach: recent news, hiring signals, pain points. Output goes into a Clay column.

Outreach layer: Instantly — $97/mo for the growth plan. Sends sequences from multiple warmed-up inboxes. We tried Zapier-based DIY sequencing and it wasn't worth the maintenance.

Inbox layer: Plain HubSpot Free for CRM, plus a $30/mo OpenAI seat for reply drafting in ChatGPT Team.

Total: ~$316/mo of recurring spend, plus usage-based fees that average another $150/mo on Clay credits. Call it $470 all-in.

How it works end-to-end

A typical week looks like this:

The sales lead loads 200 new ICP companies into Clay (sourced from Apollo or a manual ICP list). Clay enrichments add firmographic data, LinkedIn employee headcount, recent funding events, and tech stack from BuiltWith.

A custom Clay AI column then runs a Perplexity query per account: "What is the company's current biggest operational priority based on news from the last 60 days?" The output is filtered — accounts that come back with a relevant priority (e.g., "expanding their support team") move to the next stage; the rest get archived.

For accounts that pass, another Clay AI column drafts the opening line of a cold email referencing that priority. The drafts are not sent automatically — the SDR reviews them in a queue and approves or edits. Approved emails sync to Instantly, which handles sending, follow-ups, and inbox warmup.

Replies route to a shared inbox. The SDR uses a custom GPT trained on our objection-handling docs to draft responses in ChatGPT Team, then sends from their own inbox.

What this stack is not good at

It's deliberately narrow. It will not:

• Run video prospecting (we don't bother)
• Sequence on LinkedIn at scale (manual only — we're not risking a ban)
• Score inbound leads (HubSpot Free is good enough for our volume)
• Forecast or coach reps (too small a team to need that)

If you need any of the above, you'll have to add tooling — usually doubling or tripling the cost.

When to upgrade

The natural ceiling on this stack is around 8 sellers and 100 booked meetings per week. Beyond that, you're hitting Clay's credit costs hard enough that a dedicated platform like Outreach or Apollo's full suite starts making financial sense.

Below that ceiling, this stack is roughly 80% as good as the $4,500/mo platforms and costs 10% as much. Reinvest the difference in hiring better SDRs.