I assume you are correct and anybody can get a cert (with max. 1 wildcard presumably) for (again presumably) one site for free?
This @state_electrician is very insistent; do you have any idea what exactly costs €15/month (according to them)? What could they mean by "LE (LetsEncrypt) equivalent"?
They seem to claim that the free cert offer is only for a limited time?
edit:
no, they explained themselves. Apparently LE gives as many free certs for as many domains as you want to any one user.