From what it sounds like, maybe I misunderstood and If i did I'm sorry, you have to pay to use/have an IRC Server. If so, that cost is a service cost to host on the company/group's computer. This is in no way related to mirc pricing. There are hundreds, if not thousands of IRC servers that require no cost or obligation, that allow users to join. For a couple, DALnet and Gamesnet both have tens of thousands of users that use their services for free.
Mirc is a chat program that allows users to connect to irc server. mIRC does cost anywhere from $10 to $40 if you were to register (my suggestion you do), but this is only a fee to show support for Khaled's product, and a way of thanking him for all his time and effort.
So I hope that answers your question. If I am completly off base, I'm sorry.