There's no sign-up and no account — just head to the Data page and get started. Your data stays on your own device; see the Privacy, security & data sovereignty page for details.
THERE ARE NO FEES OR CHARGES.
Causal Wizard is free and open source, for educational purposes. The site itself runs entirely in your browser - there's no server-side computation to pay for, since the actual statistical fitting happens in a notebook on your own computer or in your own Google Colab session. There's nothing to subscribe to and nothing planned.