Prison Reform

I have heard that prisons drink much of the government's money, and overcrowding supposedly necessitates the death penalty for the sake of keeping the cost down. What are the issues with prisons? Educate everyone else if you know. Then let's think about what should be done to address them.

Before knowing the real issues, here are my questions about how to solve the money one: Which prisoners would we be willing to release as a society? Should the prisoners somehow be funding the prisons through labor?