You can make enough to pay for one or two nice video cards easily enough, or at least cover most of their cost. If that's what you're trying to do, go for it. As far as making "real money" at it no one really knows. Do your own homework and decide for yourself.
As I said, if it allowed me to eventually get a pair of new video cards, then I'd more than likely be happy. In all reality, I work and I'd never expect to make the kind of money that I do in my real job. It would be nice to have a tiny extra bit of income though. I'd never expect much though, unless I build and invested in a mining operation of my own.