Quotes for AI projects usually cover the build. The running costs arrive later and surprise people. There are four, and each can be estimated before you commit.
Model usage
You pay per unit of text, audio or image processed. Estimate it from volume: requests per month, multiplied by typical size, multiplied by the model's price. Then design to lower it: use a smaller model for easy steps, cache repeated work, and trim what you send. Differences of five to ten times between a careless and a careful design are common.
Infrastructure
Hosting, databases, search indexes, queues and logs. For most small and mid-sized deployments this is modest beside model usage, provided nobody leaves large resources running idle.
Maintenance
Models are retired and replaced. APIs you connect to change. Your own products, prices and policies change. A system nobody maintains drifts out of date within months. Budget time every month for updates and re-testing.
Oversight
Someone should review a sample of outputs, look at the exceptions queue and read the monthly numbers. An hour or two a week is typical. It is the cheapest insurance you will buy.
Ask any vendor, including us, for a twelve-month cost view before signing: build, plus these four lines. If they can't produce one, they have not thought about month seven.