Buddy, you can get a certificate for less than FIVE US dollars per year. Is that too much for you?
Actually yes, frankly it is. Because according to Google's overpaid, brain-dead Chrome developers, I need one for the KVM, one for each of the management cards in the servers, one for each of the appliances I have (from DVRs to firewalls etc), one for each little device with a web server (assuming it even supports writing a certificate to storage, and config for HTTPS), one for each workstation or server with an app or config UI. Quick count for my house alone