It's a $270 billion industry, but how exactly do you make a profit from locking folks up? In part three of our 4-part series, we break down the cost of incarceration in America, for both taxpayers and those who end up behind bars, and we take a hard look at how prison became big business. For more on the criminal justice system, check out "The Redemption Project with Van Jones," airing Sunday nights at 9 PM ET/PT on CNN and CNN.com/go, or visit www.cnn.com/redemption.

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