What Does AI Cost to Run Each Month? The Bills After the Build

Everyone talks about the build price. Almost nobody talks about the bill that arrives every month afterwards.

I have written before about what AI automation should cost to build and what a chatbot costs. This one is about what comes after. The running costs. Because that is the number that decides whether the thing is still worth having in a year.

The honest monthly figure for a small business

For a small UK business with one or two AI tools doing real work, the running cost is usually somewhere between twenty and a hundred pounds a month.

Not hundreds. Not thousands. If you are being quoted more than that for tools that are already built and working, somebody should be able to show you exactly where the money goes.

Here is where it actually goes.

The five lines on the bill

The AI itself. Every time the tool reads an enquiry or writes a reply, it uses a model from a company like OpenAI, Anthropic or Google, and you pay for what it uses. For a small business handling a few hundred enquiries a month, that is usually a few pounds. On a bigger, more expensive model it might be twenty or thirty. It is the line people worry about most and the one that is almost always smallest.

Somewhere for it to live. The tool has to run on a server. For one business, a small one costs five to thirty pounds a month. If it needs to store a lot of documents or history, a bit more.

The software it plugs into. If the tool connects your website to your diary or your accounts through a service like Zapier or Make, those have their own subscriptions. Twenty pounds a month is typical at small business volumes. Sometimes you already pay for these and the tool just uses them.

The channels it talks through. Answering on your website costs nothing extra. WhatsApp and text messages can carry small charges per message depending on how they are sent. Pennies each, but worth knowing about before you switch it on for every customer.

Someone looking after it. This is the one that varies most. Software changes, your prices change, a supplier updates their system and something stops talking to something else. Somebody has to notice and fix it. That can be you, or it can be a retainer with whoever built it.

The lesson I learned the expensive way

I run a team of AI agents across my own businesses. They find customers, chase what is outstanding and report back to me every morning.

A few weeks ago I found some of them had been left on a bigger, pricier AI model than they needed. That mistake cost me eighteen dollars in one day, for work a cheaper model does just as well. Not a disaster. But over a month it would have been more than five hundred dollars for nothing.

That is how running costs creep. Nobody decides to spend more. A setting gets left on the wrong option and nobody is watching the bill.

So whoever builds your tool should tell you which model it runs on and why, and what it should cost you a month. You should check that number against your actual bill for the first three months. If it does not match, ask.

A worked example

Say you run a trade business. You have a tool that answers enquiries on your website out of hours, collects the job details, and sends you a tidy summary in the morning.

Around three hundred enquiries a month. Roughly:

AI usage: five pounds.
Server: fifteen pounds.
Connection to your diary: twenty pounds.

Forty pounds a month. If it catches one job a month that you would otherwise have lost, it has paid for itself many times over. If it catches none, you should switch it off, and you have lost forty pounds finding out.

That is the test for every monthly bill. What does it cost, and what would I lose without it?

When a monthly fee is fair and when it is not

A retainer for looking after your tools is fair when real work happens every month and you can see it. New things built. Problems fixed before you noticed them. A short note telling you what changed.

It is not fair when the tool was finished a year ago, nothing has changed since, and the fee is still going out. A working tool mostly sits there working. You should not pay somebody hundreds a month to watch it.

My own retainer is from eight hundred pounds a month, and it only makes sense for a business that wants new things built as it grows. For a business that just needs one tool kept running, it is too much, and I will tell you so. The full details are on work with me.

Four questions to ask before you sign anything

What will this cost me a month to run, line by line? A proper answer takes two minutes. A vague one is a warning.

Which AI model does it use, and could a cheaper one do the job? Often it could.

Can I see every charge? Either the accounts are in your name, or every line is itemised on your invoice. Never one lump figure.

What happens if I stop paying you? Get the answer in writing before you start. Some tools keep working on their own. Some live on the builder's server and stop when the fee stops. Both can be fair, as long as you knew which one you were buying.

If you are still deciding whether any of this is worth doing, start with what to automate first. It will save you from paying monthly for something that was never the real problem.

The short version

Build costs are a one time decision. Running costs are a decision you make every month without noticing. Keep them small, keep them in your name, and check them.

If you want someone to look at what you are paying now and tell you honestly whether it is worth it, get in touch. I read every message myself. And if you want the longer story of why I care so much about small businesses not getting milked, it is in my book.