The contracts may have changed but in general, the kids didn't get anything more than "fame" and free rent originally. Some of the kids were upset that they didn't get a cut of the video sales. Now episodes of the Real World are broadcast in commercial syndication on other networks making more $$$ for Viacom but no more for the participants.
They put themselves in their predicament but I have to wonder if they really knew what they were getting into.
As far as paying the participants of The Real World, I say tough crap for them. Seriously. How much would they have to spend to rent the luxuirious pads that they live in, not to mention to get the furniture that is in them.
I bet if they all pooled their money together they couldnt rent the Manhattan and SF pads that they were living in, let alone furnish them.