SO, the way the Hotspot printers work (as I understand it) is, you plug them in and give them internet access and there is a label on the front with the printers email address.
You email your document to the printer and it prints. You can optionally require that the submitter pay a fee via credit card (provider takes a cut of that)before it prints.
So, the service fees for this would cover the email address, not an IP as the printer is sitting on your network, presumably behind firewalls, etc.