Hi there… 
Isn’t it simple? Just add the Replit AI cost to your hours multiplied by your hourly rate for the total price.
Anyways: The Hours x Rate formula works, but remember to factor in value. If you build a site in 8 hours using AI that normally takes 35+, charge for the value of the website, not just the 8 hours. Also, clarify who covers hosting and ongoing AI API token costs, as these can be expensive for the client.