I remember calling up Network Solutions on the phone to pay for a domain, because they had no e-commerce functionality! This was around 1997ish. I had several "free" domains from the 1993-94 era.
Yep and they sent out these paper invoices and gave people credit when they registered. So much profit they could afford to not get paid in many cases once they started to charge for the domains. I also remember (as I'm sure you) some billings going out with ads for branded tshirts with their name on it and some other swag.