Would setting up my own mail server be a viable option for freelance clients who need email? When doing freelance web development I always offer to host my clients sites and they almost always ask about email addresses. No that google and microsoft don't offer free custom domain email addresses anymore I've had to tell them it will cost or I can set them up with zoho.

I've been wanting to set up my own email server and wouldn't mind offering the service to clients for free (obviously that would be after I get very used to administrating an email server). Would that be a horrible idea? Are there any specific laws or regulations in the US I would need to know about before providing email to clients?