The United States alone spends over $100 billion per year on prisons. Each prisoner costs around $70,000 But we now know: 1. People who commit crimes usually do so due to a bunch of reasons that we are increasingly understanding better all the time. 2 exposure to prisons increases risk of recidivism 3, ways of keeping people secure in their own homes - ankle bracelets and surveillance technology. so why don't we just use prisons for those who are the most potent risk to society? Phase out prisons.