It costs hundreds a month for the customer, but way more for the companies. Try claude code, it's pay as you go, and it's like .5$ to 1$ per task, and it doesn't even complete it well, so if you make it work 24/7, I'm pretty sure it's gonna swallow your money for a result weaker than with a regular engineer. Moreover, you need someone to check what the AI is doing AND you need to prompt it properly (unless the CEO is willing to do that himself)
So right now, I have a really hard time seeing LLMs as a well-spent money if they were bought at their real cost