If porn is free on the Internet, then how do porn stars actually make money? On the Skeptics Stack Exchange, porn is estimated to generate 57 billion dollars a year in America.  However, I've never once paid for porn, and I don't know of any other friends, classmates, students who pay for porn either.

What I am missing?  Is there porn that's targeted at wealthier, paying customers that I am not aware of?

Seems like porn is in great demand, but there's also a great supply of Internet porn, too, and thus anyone can consume porn for free these days...
Using Google is also free, yet the firm is quite profitable, so a possible solution could be ad revenue.

Another solution could be that your sampling is off. E.g. most urban Democrats do not know many rural Republicans and vice-versa. It is similarly possible that people who do pay for porn do not move in your social circle.

There is also an incentive issue to your sampling. This is a subject most people probably do not wish to discuss. As such you can reasonably doubt if you are getting honest answers. If one were to answer your question in the affirmitive, he would incur not only the stigma of watching porn, but also the stigma of having paid for it, which as you say is kind of strange given its free availability.