The short answer: less than one client visit a month to run, and $49 to set up properly. A general AI assistant has a free tier that is enough to start, and a paid account costs about what one basic service brings in. The real cost of AI is not the subscription. It is the weeks people lose using it badly, and the money spent on big consulting projects they did not need.
The costly path is signing up for a broad "AI transformation" from someone who has never run a business like yours, before anyone has looked at your actual numbers. Before you commit to anything sizeable, ask for the specific opportunities in your business, ranked, with what each is worth. If they cannot name them, the project is for their business, not yours.
Your future clients are already asking AI assistants who to book with and search engines who to trust. Every month your admin eats your evenings is a month of that time not going into clients, your craft, or the marketing that fills your book. The honest total to get properly started is $49 and an afternoon. That is the whole barrier.