ifaxapp

While ifax is a conventional (registration-requiring) online fax service provider, it does offer one-off (registrationless) online faxing. The service costs $1.99 per page. The service has a Trustpilot score of 4 based on 311 reviews (last updated 04 Jun 2023), which appears to refer mostly to the conventional variant. https://ifaxapp.com/pay-per-fax-online