Now Playing: 06-06-12 Marketplace

General Motors is facing a pension crisis. To save themselves more than $20 billion in pension obligations, they're giving big buyouts to some retirees. A new study shows that having a trade certificate under your belt dramatically improves your salary. Compared to earlier this year, oil prices are way down -- so when will our wallets notice the difference? We hears from listeners about their thoughts on last week's View Park story and about what it means to be middle class. And Kai Ryssdal talks to Nobel Prize-winning economist Joseph Stiglitz about how inequality harms our economy.