Forget the $99/mo SaaS pricing pages. Here's what a real custom AI agent actually costs to build, run, and maintain — engineering hours, infra, model spend, evaluation, on-call. Plus the breakeven math vs the human team it replaces.
Pricing note, 5 September 2026. Our published prices changed on this date: Operators moved from $4,950 build / $1,997 per month to $7,500 / $2,950, and Agent in a Day moved from $497 one-time to $2,500 build / $497 per month. The arithmetic below was run against the prices in force when it was written and has been left as it was rather than quietly restated. Current prices are on the pricing page.
Every founder who asks "what does a custom agent cost?" is really asking three different questions stacked on top of each other:
The SaaS pricing pages with the big "$99/mo" headline only answer about 20% of question 2. The rest is in the footnotes. Here's the bottom-up math, the way I actually quote deals.
Our typical custom-build fee at TrainYourAgent is $9,950. Here's where every dollar goes for a representative install (mid-complexity, two integrations, single-channel voice agent):
| Line item | Hours | Loaded rate | Cost |
|---|---|---|---|
| Discovery + scope doc | 6 | $250/hr | $1,500 |
| System prompt + persona engineering | 8 | $250/hr | $2,000 |
| Knowledge-base extraction + chunking | 6 | $250/hr | $1,500 |
| Integration #1 (CRM or PMS) | 8 | $250/hr | $2,000 |
| Integration #2 (calendar or telephony) | 6 | $250/hr | $1,500 |
| Evaluation suite (20 test cases) | 6 | $250/hr | $1,500 |
| Telephony provisioning + SIP routing | 3 | $250/hr | $750 |
| Production hardening + handoff | 4 | $250/hr | $1,000 |
| Total engineering | 47 hrs | $11,750 | |
| Founder margin reduction (discounted) | -$1,800 | ||
| Quoted price | $9,950 |
The fully-loaded engineering rate of $250/hr reflects: senior IC pay, payroll burden, benefits, software stack (Vapi, Pinecone, monitoring, eval tooling), proration of office/admin overhead, sales acquisition cost, and ~25% gross-margin retained for the business. Below that rate, you're either using contractors who'll disappear when you need them, or you're building the wrong company.
For deals priced below $9,950, the scope is genuinely smaller — single integration, no telephony, off-the-shelf knowledge base. Below $5,000 you should be on a SaaS template.
This is where most SMBs get surprised. Here's the breakdown for a realistic month at 600 calls / 4 min avg:
Model spend (the LLM itself)
Telephony
Speech (STT + TTS)
Vector / RAG infrastructure
Observability + analytics
Total run cost: $259/mo
For 600 calls, that's $0.43 per call landed. Cheaper than a single Bing-clicked ad lead.
This is the one the bargain-bin agencies don't price in. After day one, an agent needs:
If you do this yourself: budget 20-30 hours/month of competent IC time. At $250/hr loaded that's $5,000-$7,500/mo — more than the cost of the agent itself.
If we maintain it for you under retainer: $1,500-$3,500/mo depending on complexity. That's why most customers stay on retainer after build — the math is straightforward.
The most useful framing for buyers is: how many months of run cost equals one quarter of a human FTE?
A US-loaded receptionist at $54K/yr = $13,500/quarter. Our typical install costs:
For three months that's $2,574 run + $9,950 build = $12,524.
You break even on day 84. Quarter two onward, the agent is pure profit on the labor-replacement side, and that's before factoring booking-rate improvements or after-hours capture.
For a $108K/yr two-person team, the breakeven drops to ~day 30.
After three years building agents for SMBs, exactly three pricing structures hold up:
1. Fixed-fee build + retainer. What we do. Clean MRR, predictable.
2. Pay-per-booked-outcome. Works when the customer has a single, easy-to-attribute conversion event (booked appointment, qualified lead, paid order). $20-50 per booked appointment is common. Bad when the customer disputes attribution.
3. Revenue share. Works for early-stage SaaS or content businesses with a clean revenue line and a long-term partnership. Bad for SMB because the accounting is painful.
Everything else (hourly, "we'll bill you what it takes") fails. Skip them.
Three patterns I see weekly:
Two patterns that destroy projects:
If you're an SMB buyer thinking about an agent, the math you should run:
If a vendor's quote violates any of those, it's the wrong vendor.
We built a Cost Estimator that runs this math against your own call volume and labor cost — gives you a 12-month TCO with all four cost components broken out. Free, no email required to see the result.
If you want a real quote on a real build: book a call. I'll run your specific numbers live during the call and email you the scope doc inside 24 hours.
An earlier version of this section was headed "cost benchmarks across deal sizes we've actually closed" and listed five tiers with retainers that do not exist and never did. That was not a sample of closed deals, and the tier ladder was invented. It has been deleted.
What replaces it is the published price list plus one assumption — a monthly run-cost line for telephony, STT, TTS and model usage that scales with volume — so you can see the twelve-month number rather than the sticker. The lanes are on the pricing page; the run-cost column is the only estimate here, and it is the one to replace with your own volume.
| Lane | Build fee | Mo retainer | Mo run cost (est.) | 12-mo TCO |
|---|---|---|---|---|
| Self-Serve (you build it) | $0 | $99 | $90 | $2,268 |
| Operators (done-for-you, 5,000 min) | $4,950 | $1,997 | $180 | $31,074 |
| Scale (multi-location, 25,000 min) | $9,950 | $4,997 | $310 | $73,634 |
| Above Scale (multi-product, custom) | scoped | scoped | $1,200+ | scoped |
The model is the same on every lane: front-load the engineering on the build fee, recover ongoing engineering effort and infra through the retainer, recover variable usage through the run-cost line. The build fee is refunded if we do not ship inside 21 days, and there is a 30-day money-back guarantee against the spec agreed on the kickoff call.
The honest test for whether you should build vs buy off-the-shelf SaaS isn't the sticker price. It's this single ratio:
(annual_revenue_from_the_use_case) / (annual_TCO_of_the_solution)
If that ratio is above 8x, you almost certainly want a custom build because the marginal improvement from a custom solution will multiply that ratio dramatically.
If that ratio is below 3x, SaaS is probably right because you can't afford the slope of investment a custom build implies.
Between 3x and 8x is the gray zone where it depends on how much your team can absorb in onboarding effort and whether the SaaS template can be customized enough to land the use case.
Most SMB voice-agent installs end up in the 12-20x range — which is why they're a category where custom builds dominate SaaS.
A non-exhaustive list of services I'm paying for every month to ship a single voice agent install:
Each of those is between $5 and $80/mo. Total infra-only cost per install: $130-$220/mo depending on volume. That's why the $259/mo run cost I quoted earlier isn't actually padding — it's just covering what real infrastructure costs in 2026.
If a vendor is quoting you $100/mo "all-in" for a custom voice agent, they're either eating the infra cost on their own balance sheet (unsustainable, you'll be repriced inside 12 months) or they're cutting corners that will bite you in production.