How to use Replit Agent: from prompt to deployed app

Replit Agent is an AI that builds a working app from a plain-language prompt inside Replit's browser IDE, then deploys it on the same page, with nothing installed on your machine. The part worth understanding before you start is the meter: Agent is billed by effort, one charge per checkpoint, and Replit does not publish a fixed price per checkpoint. This is the whole thing, first prompt to live URL, and how the billing actually works.